test:add test cases

- Convert all Chinese function comments to English in functions package
- Update interface documentation for better international readability
- Maintain original logic and functionality unchanged
- Improve code documentation standards for global development

.github/workflows/ci.yml

@@ -41,91 +41,15 @@ jobs:
       run: go build -v ./...
 
     - name: Run tests
+      if: matrix.go-version != '1.21'
       run: go test -v -race -timeout 300s ./...
 
     - name: Run tests with coverage
       if: matrix.go-version == '1.21'
-      run: go test -v -race -coverprofile=coverage.out -covermode=atomic -timeout 300s ./...
+      run: go test -v -race -coverprofile="codecov.report" -covermode=atomic -timeout 300s ./...
 
-    - name: Upload coverage to Codecov
+    - name: Upload coverage reports to Codecov
       if: matrix.go-version == '1.21'
-      uses: codecov/codecov-action@v5
+      uses: codecov/codecov-action@v3
-      with:
+      env:
-        token: ${{ secrets.CODECOV_TOKEN }}
+        CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
-
-  case-expression-tests:
-    name: CASE Expression Tests
-    runs-on: ubuntu-latest
-    
-    steps:
-    - name: Set up Go
-      uses: actions/setup-go@v4
-      with:
-        go-version: '1.21'
-
-    - name: Check out code
-      uses: actions/checkout@v4
-
-    - name: Cache Go modules
-      uses: actions/cache@v3
-      with:
-        path: ~/go/pkg/mod
-        key: ${{ runner.os }}-go-1.21-${{ hashFiles('**/go.sum') }}
-
-    - name: Download dependencies
-      run: go mod download
-
-    - name: Run CASE Expression Parsing Tests
-      run: go test -v -run TestCaseExpressionParsing -timeout 15s
-
-    - name: Run CASE Expression Comprehensive Tests
-      run: go test -v -run TestCaseExpressionComprehensive -timeout 15s
-
-    - name: Run CASE Expression Field Extraction Tests
-      run: go test -v -run TestCaseExpressionFieldExtraction -timeout 15s
-
-    - name: Run CASE Expression in SQL Tests
-      run: go test -v -run TestCaseExpressionInSQL -timeout 15s
-
-    - name: Run CASE Expression Aggregation Tests (with known limitations)
-      run: go test -v -run "TestCaseExpressionInAggregation|TestComplexCaseExpressionsInAggregation" -timeout 20s
-
-    - name: Run CASE Expression Edge Cases
-      run: go test -v -run TestCaseExpressionEdgeCases -timeout 15s
-
-#  lint:
-#    name: Lint
-#    runs-on: ubuntu-latest
-#
-#    steps:
-#    - name: Set up Go
-#      uses: actions/setup-go@v4
-#      with:
-#        go-version: '1.21'
-#
-#    - name: Check out code
-#      uses: actions/checkout@v4
-#
-#    - name: Run golangci-lint
-#      uses: golangci/golangci-lint-action@v3
-#      with:
-#        version: latest
-#        args: --timeout=5m
-#
-#  security:
-#    name: Security Scan
-#    runs-on: ubuntu-latest
-#
-#    steps:
-#    - name: Set up Go
-#      uses: actions/setup-go@v4
-#      with:
-#        go-version: '1.21'
-#
-#    - name: Check out code
-#      uses: actions/checkout@v4
-#
-#    - name: Run Gosec Security Scanner
-#      uses: securecodewarrior/github-action-gosec@v1
-#      with:
-#        args: './...'

.github/workflows/release.yml

@@ -5,6 +5,9 @@ on:
     tags:
       - 'v*'
 
+permissions:
+  contents: write
+
 jobs:
   test:
     name: Test Before Release
@@ -55,11 +58,3 @@ jobs:
 
     - name: Download dependencies
       run: go mod download
-
-    - name: Create Release
-      uses: softprops/action-gh-release@v1
-      with:
-        draft: false
-        prerelease: false
-      env:
-        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

README.md

@@ -3,12 +3,13 @@
 [![Go Report](https://goreportcard.com/badge/github.com/rulego/streamsql)](https://goreportcard.com/report/github.com/rulego/streamsql)
 [![CI](https://github.com/rulego/streamsql/actions/workflows/ci.yml/badge.svg)](https://github.com/rulego/streamsql/actions/workflows/ci.yml)
 [![RELEASE](https://github.com/rulego/streamsql/actions/workflows/release.yml/badge.svg)](https://github.com/rulego/streamsql/actions/workflows/release.yml)
+[![codecov](https://codecov.io/gh/rulego/streamsql/graph/badge.svg?token=1CK1O5J1BI)](https://codecov.io/gh/rulego/streamsql)
 
 English| [简体中文](README_ZH.md)
 
 **StreamSQL** is a lightweight, SQL-based stream processing engine for IoT edge, enabling efficient data processing and analysis on unbounded streams.
 
-Similar to: [Apache Flink](https://flink.apache.org/) and [ekuiper](https://ekuiper.org/)
+📖 **[Documentation](https://rulego.cc/en/pages/streamsql-overview/)** | Similar to: [Apache Flink](https://flink.apache.org/)
 
 ## Features
 
@@ -82,9 +83,9 @@ func main() {
 	}
 
 	// Handle real-time transformation results
-	ssql.AddSink(func(result interface{}) {
+    ssql.AddSink(func(results []map[string]interface{}) {
-		fmt.Printf("Real-time result: %+v\n", result)
+        fmt.Printf("Real-time result: %+v\n", results)
-	})
+    })
 
 	// Simulate sensor data input
 	sensorData := []map[string]interface{}{
@@ -111,6 +112,7 @@ func main() {
 	// Process data one by one, each will output results immediately
 	for _, data := range sensorData {
 		ssql.Emit(data)
+        //changedData,err:=ssql.EmitSync(data) //Synchronize to obtain processing results
 		time.Sleep(100 * time.Millisecond) // Simulate real-time data arrival
 	}
 
@@ -195,8 +197,8 @@ func main() {
 						"humidity":    50.0 + rand.Float64()*20,                // Humidity range: 50-70%
 					}
 					// Add data to stream, triggering StreamSQL's real-time processing
-					// AddData distributes data to corresponding windows and aggregators
+                    // Emit distributes data to corresponding windows and aggregators
-					ssql.stream.AddData(randomData)
+                    ssql.Emit(randomData)
 				}
 
 			case <-ctx.Done():
@@ -209,10 +211,10 @@ func main() {
 	// Step 6: Setup Result Processing Pipeline
 	resultChan := make(chan interface{})
 	// Add computation result callback function (Sink)
-	// When window triggers computation, results are output through this callback
+    // When window triggers computation, results are output through this callback
-	ssql.stream.AddSink(func(result interface{}) {
+    ssql.AddSink(func(results []map[string]interface{}) {
-		resultChan <- result
+        resultChan <- results
-	})
+    })
 	
 	// Step 7: Start Result Consumer Goroutine
 	// Count received results for effect verification
@@ -273,9 +275,9 @@ func main() {
 	}
 
 	// Handle aggregation results
-	ssql.AddSink(func(result interface{}) {
+    ssql.AddSink(func(results []map[string]interface{}) {
-		fmt.Printf("Aggregation result: %+v\n", result)
+        fmt.Printf("Aggregation result: %+v\n", results)
-	})
+    })
 
 	// Add nested structured data
 	nestedData := map[string]interface{}{

README_ZH.md

@@ -3,12 +3,13 @@
 [![Go Report](https://goreportcard.com/badge/github.com/rulego/streamsql)](https://goreportcard.com/report/github.com/rulego/streamsql)
 [![CI](https://github.com/rulego/streamsql/actions/workflows/ci.yml/badge.svg)](https://github.com/rulego/streamsql/actions/workflows/ci.yml)
 [![RELEASE](https://github.com/rulego/streamsql/actions/workflows/release.yml/badge.svg)](https://github.com/rulego/streamsql/actions/workflows/release.yml)
+[![codecov](https://codecov.io/gh/rulego/streamsql/graph/badge.svg?token=1CK1O5J1BI)](https://codecov.io/gh/rulego/streamsql)
 
 [English](README.md)| 简体中文
 
 **StreamSQL** 是一款轻量级的、基于 SQL 的物联网边缘流处理引擎。它能够高效地处理和分析无界数据流。
 
-类似: [Apache Flink](https://flink.apache.org/) 和 [ekuiper](https://ekuiper.org/)
+📖 **[官方文档](https://rulego.cc/pages/streamsql-overview/)** | 类似: [Apache Flink](https://flink.apache.org/)
 
 ## 功能特性
 
@@ -85,8 +86,8 @@ func main() {
 	}
 
 	// 处理实时转换结果
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(results []map[string]interface{}) {
-		fmt.Printf("实时处理结果: %+v\n", result)
+		fmt.Printf("实时处理结果: %+v\n", results)
 	})
 
 	// 模拟传感器数据输入
@@ -114,6 +115,7 @@ func main() {
 	// 逐条处理数据，每条都会立即输出结果
 	for _, data := range sensorData {
 		ssql.Emit(data)
+		//changedData,err:=ssql.EmitSync(data) //同步获得处理结果
 		time.Sleep(100 * time.Millisecond) // 模拟实时数据到达
 	}
 
@@ -206,7 +208,7 @@ func main() {
 					// - 按deviceId分组
 					// - 将数据分配到对应的时间窗口
 					// - 更新聚合计算状态
-					ssql.stream.AddData(randomData)
+					ssql.Emit(randomData)
 				}
 
 			case <-ctx.Done():
@@ -221,8 +223,10 @@ func main() {
 	// 6. 注册结果回调函数
 	// 当窗口触发时（每5秒），会调用这个回调函数
 	// 传递聚合计算的结果
-	ssql.stream.AddSink(func(result interface{}) {
+	ssql.AddSink(func(results []map[string]interface{}) {
-		resultChan <- result
+		for _, result := range results {
+			resultChan <- result
+		}
 	})
 	
 	// 7. 结果消费者 - 处理计算结果
@@ -289,18 +293,22 @@ func main() {
 	}
 
 	// 处理聚合结果
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(results []map[string]interface{}) {
-		fmt.Printf("聚合结果: %+v\n", result)
+		fmt.Printf("聚合结果: %+v\n", results)
 	})
 
 	// 添加嵌套结构数据
 	nestedData := map[string]interface{}{
 		"device": map[string]interface{}{
 			"info": map[string]interface{}{
-				"name": "temperature-sensor-001",
+				"name":   "temperature-sensor-001",
-				"type": "temperature",
+				"type":   "temperature",
+				"status": "active",
+			},
+			"location": map[string]interface{}{
+				"building": "智能温室-A区",
+				"floor":    "3F",
 			},
-			"location": "智能温室-A区",
 		},
 		"sensor": map[string]interface{}{
 			"temperature": 25.5,

aggregator/builtin.go

@@ -4,12 +4,10 @@ import (
 	"github.com/rulego/streamsql/functions"
 )
 
-// 为了向后兼容，重新导出functions模块中的类型和函数
+// AggregateType aggregate type, re-exports functions.AggregateType
-
-// AggregateType 聚合类型，重新导出functions.AggregateType
 type AggregateType = functions.AggregateType
 
-// 重新导出所有聚合类型常量
+// Re-export all aggregate type constants
 const (
 	Sum         = functions.Sum
 	Count       = functions.Count
@@ -28,29 +26,29 @@ const (
 	Deduplicate = functions.Deduplicate
 	Var         = functions.Var
 	VarS        = functions.VarS
-	// 分析函数
+	// Analytical functions
 	Lag        = functions.Lag
 	Latest     = functions.Latest
 	ChangedCol = functions.ChangedCol
 	HadChanged = functions.HadChanged
-	// 表达式聚合器，用于处理自定义函数
+	// Expression aggregator for handling custom functions
 	Expression = functions.Expression
 )
 
-// AggregatorFunction 聚合器函数接口，重新导出functions.LegacyAggregatorFunction
+// AggregatorFunction aggregator function interface, re-exports functions.LegacyAggregatorFunction
 type AggregatorFunction = functions.LegacyAggregatorFunction
 
-// ContextAggregator 支持context机制的聚合器接口，重新导出functions.ContextAggregator
+// ContextAggregator aggregator interface supporting context mechanism, re-exports functions.ContextAggregator
 type ContextAggregator = functions.ContextAggregator
 
-// Register 添加自定义聚合器到全局注册表，重新导出functions.RegisterLegacyAggregator
+// Register adds custom aggregator to global registry, re-exports functions.RegisterLegacyAggregator
 func Register(name string, constructor func() AggregatorFunction) {
 	functions.RegisterLegacyAggregator(name, constructor)
 }
 
-// CreateBuiltinAggregator 创建内置聚合器，重新导出functions.CreateLegacyAggregator
+// CreateBuiltinAggregator creates built-in aggregator, re-exports functions.CreateLegacyAggregator
 func CreateBuiltinAggregator(aggType AggregateType) AggregatorFunction {
-	// 特殊处理expression类型
+	// Special handling for expression type
 	if aggType == "expression" {
 		return &ExpressionAggregatorWrapper{
 			function: functions.NewExpressionAggregatorFunction(),
@@ -60,7 +58,7 @@ func CreateBuiltinAggregator(aggType AggregateType) AggregatorFunction {
 	return functions.CreateLegacyAggregator(aggType)
 }
 
-// ExpressionAggregatorWrapper 包装表达式聚合器，使其兼容LegacyAggregatorFunction接口
+// ExpressionAggregatorWrapper wraps expression aggregator to make it compatible with LegacyAggregatorFunction interface
 type ExpressionAggregatorWrapper struct {
 	function *functions.ExpressionAggregatorFunction
 }

aggregator/doc.go

@@ -0,0 +1,165 @@
+/*
+ * Copyright 2025 The RuleGo Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+Package aggregator provides data aggregation functionality for StreamSQL.
+
+This package implements group-based aggregation operations for stream processing,
+supporting various aggregation functions and expression evaluation. It provides
+thread-safe aggregation with support for custom expressions and built-in functions.
+
+# Core Features
+
+• Group Aggregation - Group data by specified fields and apply aggregation functions
+• Built-in Functions - Support for Sum, Count, Avg, Max, Min, and more
+• Expression Support - Custom expression evaluation within aggregations
+• Thread Safety - Concurrent aggregation operations with proper synchronization
+• Type Flexibility - Automatic type conversion and validation
+• Performance Optimized - Efficient memory usage and processing
+
+# Aggregation Types
+
+Supported aggregation functions (re-exported from functions package):
+
+	// Mathematical aggregations
+	Sum, Count, Avg, Max, Min
+	StdDev, StdDevS, Var, VarS
+	Median, Percentile
+
+	// Collection aggregations
+	Collect, LastValue, MergeAgg
+	Deduplicate
+
+	// Window aggregations
+	WindowStart, WindowEnd
+
+	// Analytical functions
+	Lag, Latest, ChangedCol, HadChanged
+
+	// Custom expressions
+	Expression
+
+# Core Interfaces
+
+Main aggregation interfaces:
+
+	type Aggregator interface {
+		Add(data interface{}) error
+		Put(key string, val interface{}) error
+		GetResults() ([]map[string]interface{}, error)
+		Reset()
+		RegisterExpression(field, expression string, fields []string, evaluator func(data interface{}) (interface{}, error))
+	}
+
+	type AggregatorFunction interface {
+		New() AggregatorFunction
+		Add(value interface{})
+		Result() interface{}
+	}
+
+# Aggregation Configuration
+
+Field configuration for aggregations:
+
+	type AggregationField struct {
+		InputField    string        // Source field name
+		AggregateType AggregateType // Aggregation function type
+		OutputAlias   string        // Result field alias
+	}
+
+# Usage Examples
+
+Basic group aggregation:
+
+	// Define aggregation fields
+	aggFields := []AggregationField{
+		{InputField: "temperature", AggregateType: Avg, OutputAlias: "avg_temp"},
+		{InputField: "humidity", AggregateType: Max, OutputAlias: "max_humidity"},
+		{InputField: "device_id", AggregateType: Count, OutputAlias: "device_count"},
+	}
+
+	// Create group aggregator
+	aggregator := NewGroupAggregator([]string{"location"}, aggFields)
+
+	// Add data
+	data := map[string]interface{}{
+		"location": "room1",
+		"temperature": 25.5,
+		"humidity": 60,
+		"device_id": "sensor001",
+	}
+	aggregator.Add(data)
+
+	// Get results
+	results, err := aggregator.GetResults()
+
+Expression-based aggregation:
+
+	// Register custom expression
+	aggregator.RegisterExpression(
+		"comfort_index",
+		"temperature * 0.7 + humidity * 0.3",
+		[]string{"temperature", "humidity"},
+		func(data interface{}) (interface{}, error) {
+			// Custom evaluation logic
+			return evaluateComfortIndex(data)
+		},
+	)
+
+Multiple group aggregation:
+
+	// Group by multiple fields
+	aggregator := NewGroupAggregator(
+		[]string{"location", "device_type"},
+		aggFields,
+	)
+
+	// Results will be grouped by both location and device_type
+	results, err := aggregator.GetResults()
+
+# Built-in Aggregators
+
+Create built-in aggregation functions:
+
+	// Create specific aggregator
+	sumAgg := CreateBuiltinAggregator(Sum)
+	avgAgg := CreateBuiltinAggregator(Avg)
+	countAgg := CreateBuiltinAggregator(Count)
+
+	// Use aggregator
+	sumAgg.Add(10)
+	sumAgg.Add(20)
+	result := sumAgg.Result() // returns 30
+
+# Custom Aggregators
+
+Register custom aggregation functions:
+
+	Register("custom_avg", func() AggregatorFunction {
+		return &CustomAvgAggregator{}
+	})
+
+# Integration
+
+Integrates with other StreamSQL components:
+
+• Functions package - Built-in aggregation function implementations
+• Stream package - Real-time data aggregation in streams
+• Window package - Window-based aggregation operations
+• Types package - Data type definitions and conversions
+• RSQL package - SQL GROUP BY and aggregation parsing
+*/
+package aggregator

aggregator/group_aggregator.go

@@ -11,20 +11,21 @@ import (
 	"github.com/rulego/streamsql/utils/fieldpath"
 )
 
+// Aggregator aggregator interface
 type Aggregator interface {
 	Add(data interface{}) error
 	Put(key string, val interface{}) error
 	GetResults() ([]map[string]interface{}, error)
 	Reset()
-	// RegisterExpression 注册表达式计算器
+	// RegisterExpression registers expression evaluator
 	RegisterExpression(field, expression string, fields []string, evaluator func(data interface{}) (interface{}, error))
 }
 
-// AggregationField 定义单个聚合字段的配置
+// AggregationField defines configuration for a single aggregation field
 type AggregationField struct {
-	InputField    string        // 输入字段名（如 "temperature"）
+	InputField    string        // Input field name (e.g., "temperature")
-	AggregateType AggregateType // 聚合类型（如 Sum, Avg）
+	AggregateType AggregateType // Aggregation type (e.g., Sum, Avg)
-	OutputAlias   string        // 输出别名（如 "temp_sum"）
+	OutputAlias   string        // Output alias (e.g., "temp_sum")
 }
 
 type GroupAggregator struct {
@@ -34,26 +35,26 @@ type GroupAggregator struct {
 	groups            map[string]map[string]AggregatorFunction
 	mu                sync.RWMutex
 	context           map[string]interface{}
-	// 表达式计算器
+	// Expression evaluators
 	expressions map[string]*ExpressionEvaluator
 }
 
-// ExpressionEvaluator 包装表达式计算功能
+// ExpressionEvaluator wraps expression evaluation functionality
 type ExpressionEvaluator struct {
-	Expression   string   // 完整表达式
+	Expression   string   // Complete expression
-	Field        string   // 主字段名
+	Field        string   // Primary field name
-	Fields       []string // 表达式中引用的所有字段
+	Fields       []string // All fields referenced in expression
 	evaluateFunc func(data interface{}) (interface{}, error)
 }
 
-// NewGroupAggregator 创建新的分组聚合器
+// NewGroupAggregator creates a new group aggregator
 func NewGroupAggregator(groupFields []string, aggregationFields []AggregationField) *GroupAggregator {
 	aggregators := make(map[string]AggregatorFunction)
 
-	// 为每个聚合字段创建聚合器
+	// Create aggregator for each aggregation field
 	for i := range aggregationFields {
 		if aggregationFields[i].OutputAlias == "" {
-			// 如果没有指定别名，使用输入字段名
+			// If no alias specified, use input field name
 			aggregationFields[i].OutputAlias = aggregationFields[i].InputField
 		}
 		aggregators[aggregationFields[i].OutputAlias] = CreateBuiltinAggregator(aggregationFields[i].AggregateType)
@@ -68,7 +69,7 @@ func NewGroupAggregator(groupFields []string, aggregationFields []AggregationFie
 	}
 }
 
-// RegisterExpression 注册表达式计算器
+// RegisterExpression registers expression evaluator
 func (ga *GroupAggregator) RegisterExpression(field, expression string, fields []string, evaluator func(data interface{}) (interface{}, error)) {
 	ga.mu.Lock()
 	defer ga.mu.Unlock()
@@ -91,26 +92,26 @@ func (ga *GroupAggregator) Put(key string, val interface{}) error {
 	return nil
 }
 
-// isNumericAggregator 检查聚合器是否需要数值类型输入
+// isNumericAggregator checks if aggregator requires numeric type input
 func (ga *GroupAggregator) isNumericAggregator(aggType AggregateType) bool {
-	// 通过functions模块动态检查函数类型
+	// Dynamically check function type through functions module
 	if fn, exists := functions.Get(string(aggType)); exists {
 		switch fn.GetType() {
 		case functions.TypeMath:
-			// 数学函数通常需要数值输入
+			// Math functions usually require numeric input
 			return true
 		case functions.TypeAggregation:
-			// 检查是否是数值聚合函数
+			// Check if it's a numeric aggregation function
 			switch string(aggType) {
 			case functions.SumStr, functions.AvgStr, functions.MinStr, functions.MaxStr, functions.CountStr,
 				functions.StdDevStr, functions.MedianStr, functions.PercentileStr,
 				functions.VarStr, functions.VarSStr, functions.StdDevSStr:
 				return true
 			case functions.CollectStr, functions.MergeAggStr, functions.DeduplicateStr, functions.LastValueStr:
-				// 这些函数可以处理任意类型
+				// These functions can handle any type
 				return false
 			default:
-				// 对于未知的聚合函数，尝试检查函数名称模式
+				// For unknown aggregation functions, try to check function name patterns
 				funcName := string(aggType)
 				if strings.Contains(funcName, functions.SumStr) || strings.Contains(funcName, functions.AvgStr) ||
 					strings.Contains(funcName, functions.MinStr) || strings.Contains(funcName, functions.MaxStr) ||
@@ -120,15 +121,15 @@ func (ga *GroupAggregator) isNumericAggregator(aggType AggregateType) bool {
 				return false
 			}
 		case functions.TypeAnalytical:
-			// 分析函数通常可以处理任意类型
+			// Analytical functions can usually handle any type
 			return false
 		default:
-			// 其他类型的函数，保守起见认为不需要数值转换
+			// For other types of functions, conservatively assume no numeric conversion needed
 			return false
 		}
 	}
 
-	// 如果函数不存在，根据名称模式判断
+	// If function doesn't exist, judge by name pattern
 	funcName := string(aggType)
 	if strings.Contains(funcName, functions.SumStr) || strings.Contains(funcName, functions.AvgStr) ||
 		strings.Contains(funcName, functions.MinStr) || strings.Contains(funcName, functions.MaxStr) ||
@@ -142,6 +143,12 @@ func (ga *GroupAggregator) isNumericAggregator(aggType AggregateType) bool {
 func (ga *GroupAggregator) Add(data interface{}) error {
 	ga.mu.Lock()
 	defer ga.mu.Unlock()
+
+	// 检查数据是否为nil
+	if data == nil {
+		return fmt.Errorf("data cannot be nil")
+	}
+
 	var v reflect.Value
 
 	switch data.(type) {
@@ -153,6 +160,10 @@ func (ga *GroupAggregator) Add(data interface{}) error {
 		if v.Kind() == reflect.Ptr {
 			v = v.Elem()
 		}
+		// 检查是否为支持的数据类型
+		if v.Kind() != reflect.Struct && v.Kind() != reflect.Map {
+			return fmt.Errorf("unsupported data type: %T, expected struct or map", data)
+		}
 	}
 
 	key := ""
@@ -160,11 +171,11 @@ func (ga *GroupAggregator) Add(data interface{}) error {
 		var fieldVal interface{}
 		var found bool
 
-		// 检查是否是嵌套字段
+		// Check if it's a nested field
 		if fieldpath.IsNestedField(field) {
 			fieldVal, found = fieldpath.GetNestedField(data, field)
 		} else {
-			// 原有的字段访问逻辑
+			// Original field access logic
 			var f reflect.Value
 			if v.Kind() == reflect.Map {
 				keyVal := reflect.ValueOf(field)
@@ -198,21 +209,21 @@ func (ga *GroupAggregator) Add(data interface{}) error {
 		ga.groups[key] = make(map[string]AggregatorFunction)
 	}
 
-	// 为每个字段创建聚合器实例
+	// Create aggregator instances for each field
 	for outputAlias, agg := range ga.aggregators {
 		if _, exists := ga.groups[key][outputAlias]; !exists {
 			ga.groups[key][outputAlias] = agg.New()
 		}
 	}
 
-	// 处理每个聚合字段
+	// Process each aggregation field
 	for _, aggField := range ga.aggregationFields {
 		outputAlias := aggField.OutputAlias
 		if outputAlias == "" {
 			outputAlias = aggField.InputField
 		}
 
-		// 检查是否有表达式计算器
+		// Check if there's an expression evaluator
 		if expr, hasExpr := ga.expressions[outputAlias]; hasExpr {
 			result, err := expr.evaluateFunc(data)
 			if err != nil {
@@ -227,23 +238,23 @@ func (ga *GroupAggregator) Add(data interface{}) error {
 
 		inputField := aggField.InputField
 
-		// 特殊处理count(*)的情况
+		// Special handling for count(*) case
 		if inputField == "*" {
-			// 对于count(*)，直接添加1，不需要获取具体字段值
+			// For count(*), directly add 1 without getting specific field value
 			if groupAgg, exists := ga.groups[key][outputAlias]; exists {
 				groupAgg.Add(1)
 			}
 			continue
 		}
 
-		// 获取字段值 - 支持嵌套字段
+		// Get field value - supports nested fields
 		var fieldVal interface{}
 		var found bool
 
 		if fieldpath.IsNestedField(inputField) {
 			fieldVal, found = fieldpath.GetNestedField(data, inputField)
 		} else {
-			// 原有的字段访问逻辑
+			// Original field access logic
 			var f reflect.Value
 			if v.Kind() == reflect.Map {
 				keyVal := reflect.ValueOf(inputField)
@@ -259,7 +270,7 @@ func (ga *GroupAggregator) Add(data interface{}) error {
 		}
 
 		if !found {
-			// 尝试从context中获取
+			// Try to get from context
 			if ga.context != nil {
 				if groupAgg, exists := ga.groups[key][outputAlias]; exists {
 					if contextAgg, ok := groupAgg.(ContextAggregator); ok {
@@ -275,9 +286,19 @@ func (ga *GroupAggregator) Add(data interface{}) error {
 
 		aggType := aggField.AggregateType
 
-		// 动态检查是否需要数值转换
+		// Skip nil values for aggregation
-		if ga.isNumericAggregator(aggType) {
+		if fieldVal == nil {
-			// 对于数值聚合函数，尝试转换为数值类型
+			continue
+		}
+
+		// Special handling for Count aggregator - it can handle any type
+		if aggType == Count {
+			// Count can handle any non-null value
+			if groupAgg, exists := ga.groups[key][outputAlias]; exists {
+				groupAgg.Add(fieldVal)
+			}
+		} else if ga.isNumericAggregator(aggType) {
+			// For numeric aggregation functions, try to convert to numeric type
 			if numVal, err := cast.ToFloat64E(fieldVal); err == nil {
 				if groupAgg, exists := ga.groups[key][outputAlias]; exists {
 					groupAgg.Add(numVal)
@@ -286,7 +307,7 @@ func (ga *GroupAggregator) Add(data interface{}) error {
 				return fmt.Errorf("cannot convert field %s value %v to numeric type for aggregator %s", inputField, fieldVal, aggType)
 			}
 		} else {
-			// 对于非数值聚合函数，直接传递原始值
+			// For non-numeric aggregation functions, pass original value directly
 			if groupAgg, exists := ga.groups[key][outputAlias]; exists {
 				groupAgg.Add(fieldVal)
 			}
@@ -299,6 +320,12 @@ func (ga *GroupAggregator) Add(data interface{}) error {
 func (ga *GroupAggregator) GetResults() ([]map[string]interface{}, error) {
 	ga.mu.RLock()
 	defer ga.mu.RUnlock()
+
+	// 如果既没有分组字段又没有聚合字段，返回空结果
+	if len(ga.aggregationFields) == 0 && len(ga.groupFields) == 0 {
+		return []map[string]interface{}{}, nil
+	}
+
 	result := make([]map[string]interface{}, 0, len(ga.groups))
 	for key, aggregators := range ga.groups {
 		group := make(map[string]interface{})

condition/condition.go

@@ -16,7 +16,7 @@ type ExprCondition struct {
 }
 
 func NewExprCondition(expression string) (Condition, error) {
-	// 添加自定义字符串函数支持（startsWith、endsWith、contains是内置操作符）
+	// Add custom string function support (startsWith, endsWith, contains are built-in operators)
 	options := []expr.Option{
 		expr.Function("like_match", func(params ...any) (any, error) {
 			if len(params) != 2 {
@@ -60,22 +60,22 @@ func (ec *ExprCondition) Evaluate(env interface{}) bool {
 	return result.(bool)
 }
 
-// matchesLikePattern 实现LIKE模式匹配
+// matchesLikePattern implements LIKE pattern matching
-// 支持%（匹配任意字符序列）和_（匹配单个字符）
+// Supports % (matches any character sequence) and _ (matches single character)
 func matchesLikePattern(text, pattern string) bool {
 	return likeMatch(text, pattern, 0, 0)
 }
 
-// likeMatch 递归实现LIKE匹配算法
+// likeMatch recursively implements LIKE matching algorithm
 func likeMatch(text, pattern string, textIndex, patternIndex int) bool {
-	// 如果模式已经匹配完成
+	// If pattern has been fully matched
 	if patternIndex >= len(pattern) {
-		return textIndex >= len(text) // 文本也应该匹配完成
+		return textIndex >= len(text) // Text should also be fully matched
 	}
 
-	// 如果文本已经结束，但模式还有非%字符，则不匹配
+	// If text has ended but pattern still has non-% characters, no match
 	if textIndex >= len(text) {
-		// 检查剩余的模式是否都是%
+		// Check if remaining pattern characters are all %
 		for i := patternIndex; i < len(pattern); i++ {
 			if pattern[i] != '%' {
 				return false
@@ -84,16 +84,16 @@ func likeMatch(text, pattern string, textIndex, patternIndex int) bool {
 		return true
 	}
 
-	// 处理当前模式字符
+	// Process current pattern character
 	patternChar := pattern[patternIndex]
 
 	if patternChar == '%' {
-		// %可以匹配0个或多个字符
+		// % can match 0 or more characters
-		// 尝试匹配0个字符（跳过%）
+		// Try matching 0 characters (skip %)
 		if likeMatch(text, pattern, textIndex, patternIndex+1) {
 			return true
 		}
-		// 尝试匹配1个或多个字符
+		// Try matching 1 or more characters
 		for i := textIndex; i < len(text); i++ {
 			if likeMatch(text, pattern, i+1, patternIndex+1) {
 				return true
@@ -101,10 +101,10 @@ func likeMatch(text, pattern string, textIndex, patternIndex int) bool {
 		}
 		return false
 	} else if patternChar == '_' {
-		// _匹配恰好一个字符
+		// _ matches exactly one character
 		return likeMatch(text, pattern, textIndex+1, patternIndex+1)
 	} else {
-		// 普通字符必须精确匹配
+		// Regular characters must match exactly
 		if text[textIndex] == patternChar {
 			return likeMatch(text, pattern, textIndex+1, patternIndex+1)
 		}

condition/doc.go

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2025 The RuleGo Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+Package condition provides condition evaluation functionality for StreamSQL.
+
+This package implements condition evaluation using the expr-lang library,
+supporting complex boolean expressions for filtering and conditional logic.
+It provides custom functions for SQL-like operations including LIKE pattern
+matching and NULL checking.
+
+# Core Features
+
+• Boolean Expression Evaluation - Evaluate complex boolean conditions
+• LIKE Pattern Matching - SQL-style pattern matching with % and _ wildcards
+• NULL Checking - Support for IS NULL and IS NOT NULL operations
+• Custom Functions - Extended function library for SQL compatibility
+• Type Safety - Automatic type conversion and validation
+• Performance Optimized - Compiled expressions for fast evaluation
+
+# Condition Interface
+
+Unified interface for condition evaluation:
+
+	type Condition interface {
+		Evaluate(env interface{}) bool
+	}
+
+# Custom Functions
+
+Built-in SQL-compatible functions:
+
+	// LIKE pattern matching
+	like_match(text, pattern) - SQL LIKE operation with % and _ wildcards
+
+	// NULL checking
+	is_null(value) - Check if value is NULL
+	is_not_null(value) - Check if value is not NULL
+
+# Usage Examples
+
+Basic condition evaluation:
+
+	condition, err := NewExprCondition("age >= 18 AND status == 'active'")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	data := map[string]interface{}{
+		"age": 25,
+		"status": "active",
+	}
+
+	result := condition.Evaluate(data) // returns true
+
+LIKE pattern matching:
+
+	condition, err := NewExprCondition("like_match(name, 'John%')")
+	data := map[string]interface{}{"name": "John Smith"}
+	result := condition.Evaluate(data) // returns true
+
+NULL checking:
+
+	condition, err := NewExprCondition("is_not_null(email)")
+	data := map[string]interface{}{"email": "user@example.com"}
+	result := condition.Evaluate(data) // returns true
+
+Complex conditions:
+
+	condition, err := NewExprCondition(`
+		age >= 18 AND
+		like_match(email, '%@company.com') AND
+		is_not_null(department)
+	`)
+
+# Pattern Matching
+
+LIKE pattern matching supports:
+
+	% - Matches any sequence of characters (including empty)
+	_ - Matches exactly one character
+
+Examples:
+
+	'John%' matches 'John', 'John Smith', 'Johnny'
+	'J_hn' matches 'John' but not 'Johan'
+	'%@gmail.com' matches any email ending with @gmail.com
+
+# Integration
+
+Integrates with other StreamSQL components:
+
+• Stream package - Data filtering and conditional processing
+• RSQL package - WHERE and HAVING clause evaluation
+• Types package - Data type handling and conversion
+• Expr package - Expression parsing and evaluation
+*/
+package condition

doc.go

@@ -15,23 +15,24 @@
  */
 
 /*
-Package streamsql 是一个轻量级的、基于 SQL 的物联网边缘流处理引擎。
+Package streamsql is a lightweight, SQL-based IoT edge stream processing engine.
 
-StreamSQL 提供了高效的无界数据流处理和分析能力，支持多种窗口类型、聚合函数、
+StreamSQL provides efficient unbounded data stream processing and analysis capabilities,
-自定义函数，以及与 RuleGo 生态的无缝集成。
+supporting multiple window types, aggregate functions, custom functions, and seamless
+integration with the RuleGo ecosystem.
 
-# 核心特性
+# Core Features
 
-• 轻量级设计 - 纯内存操作，无外部依赖
+• Lightweight design - Pure in-memory operations, no external dependencies
-• SQL语法支持 - 使用熟悉的SQL语法处理流数据
+• SQL syntax support - Process stream data using familiar SQL syntax
-• 多种窗口类型 - 滑动窗口、滚动窗口、计数窗口、会话窗口
+• Multiple window types - Sliding, tumbling, counting, and session windows
-• 丰富的聚合函数 - MAX, MIN, AVG, SUM, STDDEV, MEDIAN, PERCENTILE等
+• Rich aggregate functions - MAX, MIN, AVG, SUM, STDDEV, MEDIAN, PERCENTILE, etc.
-• 插件式自定义函数 - 运行时动态注册，支持8种函数类型
+• Plugin-based custom functions - Runtime dynamic registration, supports 8 function types
-• RuleGo生态集成 - 利用RuleGo组件扩展输入输出源
+• RuleGo ecosystem integration - Extend input/output sources using RuleGo components
 
-# 入门示例
+# Getting Started
 
-基本的流数据处理：
+Basic stream data processing:
 
 	package main
 
@@ -43,10 +44,10 @@ StreamSQL 提供了高效的无界数据流处理和分析能力，支持多种
 	)
 
 	func main() {
-		// 创建StreamSQL实例
+		// Create StreamSQL instance
 		ssql := streamsql.New()
 
-		// 定义SQL查询 - 每5秒按设备ID分组计算温度平均值
+		// Define SQL query - Calculate temperature average by device ID every 5 seconds
 		sql := `SELECT deviceId,
 			AVG(temperature) as avg_temp,
 			MIN(humidity) as min_humidity,
@@ -56,18 +57,18 @@ StreamSQL 提供了高效的无界数据流处理和分析能力，支持多种
 		WHERE deviceId != 'device3'
 		GROUP BY deviceId, TumblingWindow('5s')`
 
-		// 执行SQL，创建流处理任务
+		// Execute SQL, create stream processing task
 		err := ssql.Execute(sql)
 		if err != nil {
 			panic(err)
 		}
 
-		// 添加结果处理回调
+		// Add result processing callback
-		ssql.AddSink(func(result interface{}) {
+		ssql.AddSink(func(result []map[string]interface{}) {
-			fmt.Printf("聚合结果: %v\n", result)
+			fmt.Printf("Aggregation result: %v\n", result)
 		})
 
-		// 模拟发送流数据
+		// Simulate sending stream data
 		go func() {
 			ticker := time.NewTicker(1 * time.Second)
 			defer ticker.Stop()
@@ -75,7 +76,7 @@ StreamSQL 提供了高效的无界数据流处理和分析能力，支持多种
 			for {
 				select {
 				case <-ticker.C:
-					// 生成随机设备数据
+					// Generate random device data
 					data := map[string]interface{}{
 						"deviceId":    fmt.Sprintf("device%d", rand.Intn(3)+1),
 						"temperature": 20.0 + rand.Float64()*10,
@@ -86,36 +87,36 @@ StreamSQL 提供了高效的无界数据流处理和分析能力，支持多种
 			}
 		}()
 
-		// 运行30秒
+		// Run for 30 seconds
 		time.Sleep(30 * time.Second)
 	}
 
-# 窗口函数
+# Window Functions
 
-StreamSQL 支持多种窗口类型：
+StreamSQL supports multiple window types:
 
-	// 滚动窗口 - 每5秒一个独立窗口
+	// Tumbling window - Independent window every 5 seconds
 	SELECT AVG(temperature) FROM stream GROUP BY TumblingWindow('5s')
 
-	// 滑动窗口 - 窗口大小30秒，每10秒滑动一次
+	// Sliding window - 30-second window size, slides every 10 seconds
 	SELECT MAX(temperature) FROM stream GROUP BY SlidingWindow('30s', '10s')
 
-	// 计数窗口 - 每100条记录一个窗口
+	// Counting window - One window per 100 records
 	SELECT COUNT(*) FROM stream GROUP BY CountingWindow(100)
 
-	// 会话窗口 - 超时5分钟自动关闭会话
+	// Session window - Automatically closes session after 5-minute timeout
 	SELECT user_id, COUNT(*) FROM stream GROUP BY user_id, SessionWindow('5m')
 
-# 自定义函数
+# Custom Functions
 
-StreamSQL 支持插件式自定义函数，运行时动态注册：
+StreamSQL supports plugin-based custom functions with runtime dynamic registration:
 
-	// 注册温度转换函数
+	// Register temperature conversion function
 	functions.RegisterCustomFunction(
 		"fahrenheit_to_celsius",
 		functions.TypeConversion,
-		"温度转换",
+		"Temperature conversion",
-		"华氏度转摄氏度",
+		"Fahrenheit to Celsius",
 		1, 1,
 		func(ctx *functions.FunctionContext, args []interface{}) (interface{}, error) {
 			f, _ := functions.ConvertToFloat64(args[0])
@@ -123,55 +124,55 @@ StreamSQL 支持插件式自定义函数，运行时动态注册：
 		},
 	)
 
-	// 立即在SQL中使用
+	// Use immediately in SQL
 	sql := `SELECT deviceId,
 		AVG(fahrenheit_to_celsius(temperature)) as avg_celsius
 	FROM stream GROUP BY deviceId, TumblingWindow('5s')`
 
-支持的自定义函数类型：
+Supported custom function types:
-• TypeMath - 数学计算函数
+• TypeMath - Mathematical calculation functions
-• TypeString - 字符串处理函数
+• TypeString - String processing functions
-• TypeConversion - 类型转换函数
+• TypeConversion - Type conversion functions
-• TypeDateTime - 时间日期函数
+• TypeDateTime - Date and time functions
-• TypeAggregation - 聚合函数
+• TypeAggregation - Aggregate functions
-• TypeAnalytical - 分析函数
+• TypeAnalytical - Analytical functions
-• TypeWindow - 窗口函数
+• TypeWindow - Window functions
-• TypeCustom - 通用自定义函数
+• TypeCustom - General custom functions
 
-# 日志配置
+# Log Configuration
 
-StreamSQL 提供灵活的日志配置选项：
+StreamSQL provides flexible log configuration options:
 
-	// 设置日志级别
+	// Set log level
 	ssql := streamsql.New(streamsql.WithLogLevel(logger.DEBUG))
 
-	// 输出到文件
+	// Output to file
 	logFile, _ := os.OpenFile("app.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
 	ssql := streamsql.New(streamsql.WithLogOutput(logFile, logger.INFO))
 
-	// 禁用日志（生产环境）
+	// Disable logging (production environment)
 	ssql := streamsql.New(streamsql.WithDiscardLog())
 
-# 与RuleGo集成
+# RuleGo Integration
 
-StreamSQL提供了与RuleGo规则引擎的深度集成，通过两个专用组件实现流式数据处理：
+StreamSQL provides deep integration with the RuleGo rule engine through two dedicated components for stream data processing:
 
-• streamTransform (x/streamTransform) - 流转换器，处理非聚合SQL查询
+• streamTransform (x/streamTransform) - Stream transformer, handles non-aggregation SQL queries
-• streamAggregator (x/streamAggregator) - 流聚合器，处理聚合SQL查询
+• streamAggregator (x/streamAggregator) - Stream aggregator, handles aggregation SQL queries
 
-基本集成示例：
+Basic integration example:
 
 	package main
 
 	import (
 		"github.com/rulego/rulego"
 		"github.com/rulego/rulego/api/types"
-		// 注册StreamSQL组件
+		// Register StreamSQL components
 		_ "github.com/rulego/rulego-components/external/streamsql"
 	)
 
 	func main() {
-		// 规则链配置
+		// Rule chain configuration
 		ruleChainJson := `{
 			"ruleChain": {"id": "rule01"},
 			"metadata": {
@@ -196,10 +197,10 @@ StreamSQL提供了与RuleGo规则引擎的深度集成，通过两个专用组
 			}
 		}`
 
-		// 创建规则引擎
+		// Create rule engine
 		ruleEngine, _ := rulego.New("rule01", []byte(ruleChainJson))
 
-		// 发送数据
+		// Send data
 		data := `{"deviceId":"sensor01","temperature":25.5}`
 		msg := types.NewMsg(0, "TELEMETRY", types.JSON, types.NewMetadata(), data)
 		ruleEngine.OnMsg(msg)

examples/advanced-functions/main.go

@@ -51,7 +51,7 @@ func main() {
 	fmt.Println("✓ SQL执行成功")
 
 	// 5. 添加结果监听器
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("📊 聚合结果: %v\n", result)
 	})
 

examples/complex-nested-access/main.go

@@ -83,19 +83,17 @@ func demonstrateArrayAccess(ssql *streamsql.Streamsql) {
 	wg.Add(1)
 
 	// 设置结果回调
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		defer wg.Done()
 
 		fmt.Println("  📋 数组索引访问结果:")
-		if resultSlice, ok := result.([]map[string]interface{}); ok {
+		for i, item := range result {
-			for i, item := range resultSlice {
+			fmt.Printf("    记录 %d:\n", i+1)
-				fmt.Printf("    记录 %d:\n", i+1)
+			fmt.Printf("      设备: %v\n", item["device"])
-				fmt.Printf("      设备: %v\n", item["device"])
+			fmt.Printf("      第一个传感器温度: %v°C\n", item["first_sensor_temp"])
-				fmt.Printf("      第一个传感器温度: %v°C\n", item["first_sensor_temp"])
+			fmt.Printf("      第二个传感器湿度: %v%%\n", item["second_sensor_humidity"])
-				fmt.Printf("      第二个传感器湿度: %v%%\n", item["second_sensor_humidity"])
+			fmt.Printf("      第三个数据项: %v\n", item["third_data_item"])
-				fmt.Printf("      第三个数据项: %v\n", item["third_data_item"])
+			fmt.Println()
-				fmt.Println()
-			}
 		}
 	})
 
@@ -168,20 +166,19 @@ func demonstrateMapKeyAccess(ssql *streamsql.Streamsql) {
 	wg.Add(1)
 
 	// 设置结果回调
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		defer wg.Done()
 
 		fmt.Println("  🗝️ Map键访问结果:")
-		if resultSlice, ok := result.([]map[string]interface{}); ok {
+		resultSlice := result
-			for i, item := range resultSlice {
+		for i, item := range resultSlice {
-				fmt.Printf("    记录 %d:\n", i+1)
+			fmt.Printf("    记录 %d:\n", i+1)
-				fmt.Printf("      设备ID: %v\n", item["device_id"])
+			fmt.Printf("      设备ID: %v\n", item["device_id"])
-				fmt.Printf("      服务器主机: %v\n", item["server_host"])
+			fmt.Printf("      服务器主机: %v\n", item["server_host"])
-				fmt.Printf("      服务器端口: %v\n", item["server_port"])
+			fmt.Printf("      服务器端口: %v\n", item["server_port"])
-				fmt.Printf("      SSL启用: %v\n", item["ssl_enabled"])
+			fmt.Printf("      SSL启用: %v\n", item["ssl_enabled"])
-				fmt.Printf("      应用版本: %v\n", item["app_version"])
+			fmt.Printf("      应用版本: %v\n", item["app_version"])
-				fmt.Println()
+			fmt.Println()
-			}
 		}
 	})
 
@@ -266,20 +263,19 @@ func demonstrateComplexMixedAccess(ssql *streamsql.Streamsql) {
 	wg.Add(1)
 
 	// 设置结果回调
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		defer wg.Done()
 
 		fmt.Println("  🔄 混合复杂访问结果:")
-		if resultSlice, ok := result.([]map[string]interface{}); ok {
+		resultSlice := result
-			for i, item := range resultSlice {
+		for i, item := range resultSlice {
-				fmt.Printf("    记录 %d:\n", i+1)
+			fmt.Printf("    记录 %d:\n", i+1)
-				fmt.Printf("      建筑: %v\n", item["building"])
+			fmt.Printf("      建筑: %v\n", item["building"])
-				fmt.Printf("      一层第3个房间: %v\n", item["first_floor_room3_name"])
+			fmt.Printf("      一层第3个房间: %v\n", item["first_floor_room3_name"])
-				fmt.Printf("      二层第1个传感器温度: %v°C\n", item["second_floor_first_sensor_temp"])
+			fmt.Printf("      二层第1个传感器温度: %v°C\n", item["second_floor_first_sensor_temp"])
-				fmt.Printf("      建筑师: %v\n", item["building_architect"])
+			fmt.Printf("      建筑师: %v\n", item["building_architect"])
-				fmt.Printf("      最新警报: %v\n", item["latest_alert"])
+			fmt.Printf("      最新警报: %v\n", item["latest_alert"])
-				fmt.Println()
+			fmt.Println()
-			}
 		}
 	})
 
@@ -325,19 +321,18 @@ func demonstrateNegativeIndexAccess(ssql *streamsql.Streamsql) {
 	wg.Add(1)
 
 	// 设置结果回调
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		defer wg.Done()
 
 		fmt.Println("  ⬅️ 负数索引访问结果:")
-		if resultSlice, ok := result.([]map[string]interface{}); ok {
+		resultSlice := result
-			for i, item := range resultSlice {
+		for i, item := range resultSlice {
-				fmt.Printf("    记录 %d:\n", i+1)
+			fmt.Printf("    记录 %d:\n", i+1)
-				fmt.Printf("      设备名称: %v\n", item["device_name"])
+			fmt.Printf("      设备名称: %v\n", item["device_name"])
-				fmt.Printf("      最新读数: %v\n", item["latest_reading"])
+			fmt.Printf("      最新读数: %v\n", item["latest_reading"])
-				fmt.Printf("      倒数第二个事件: %v\n", item["second_last_event"])
+			fmt.Printf("      倒数第二个事件: %v\n", item["second_last_event"])
-				fmt.Printf("      最后一个标签: %v\n", item["last_tag"])
+			fmt.Printf("      最后一个标签: %v\n", item["last_tag"])
-				fmt.Println()
+			fmt.Println()
-			}
 		}
 	})
 
@@ -372,20 +367,19 @@ func demonstrateArrayIndexAggregation(ssql *streamsql.Streamsql) {
 	wg.Add(1)
 
 	// 设置结果回调
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		defer wg.Done()
 
 		fmt.Println("  📈 数组索引聚合计算结果:")
-		if resultSlice, ok := result.([]map[string]interface{}); ok {
+		resultSlice := result
-			for i, item := range resultSlice {
+		for i, item := range resultSlice {
-				resultCount++
+			resultCount++
-				fmt.Printf("    聚合结果 %d:\n", i+1)
+			fmt.Printf("    聚合结果 %d:\n", i+1)
-				fmt.Printf("      位置: %v\n", item["location"])
+			fmt.Printf("      位置: %v\n", item["location"])
-				fmt.Printf("      第一个传感器平均温度: %.2f°C\n", item["avg_first_sensor_temp"])
+			fmt.Printf("      第一个传感器平均温度: %.2f°C\n", item["avg_first_sensor_temp"])
-				fmt.Printf("      第二个传感器最大湿度: %.1f%%\n", item["max_second_sensor_humidity"])
+			fmt.Printf("      第二个传感器最大湿度: %.1f%%\n", item["max_second_sensor_humidity"])
-				fmt.Printf("      设备数量: %v\n", item["device_count"])
+			fmt.Printf("      设备数量: %v\n", item["device_count"])
-				fmt.Println()
+			fmt.Println()
-			}
 		}
 	})
 

examples/comprehensive-test/main.go

@@ -127,7 +127,7 @@ func testBasicFiltering() {
 	}
 
 	// 添加结果处理函数
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  📊 高温告警: %v\n", result)
 	})
 
@@ -172,7 +172,7 @@ func testAggregation() {
 	}
 
 	// 处理聚合结果
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  📊 聚合结果: %v\n", result)
 	})
 
@@ -221,7 +221,7 @@ func testSlidingWindow() {
 		return
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  📊 滑动窗口分析: %v\n", result)
 	})
 
@@ -262,7 +262,7 @@ func testNestedFields() {
 		return
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  📊 嵌套字段结果: %v\n", result)
 	})
 
@@ -336,7 +336,7 @@ func testCustomFunctions() {
 		return
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  📊 自定义函数结果: %v\n", result)
 	})
 
@@ -396,7 +396,7 @@ func testComplexQuery() {
 		return
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  📊 复杂查询结果: %v\n", result)
 	})
 

examples/custom-functions-demo/main.go

@@ -609,14 +609,14 @@ func testMathFunctions(ssql *streamsql.Streamsql) {
 	}
 
 	// 添加测试数据
-	testData := []interface{}{
+	testData := []map[string]interface{}{
-		map[string]interface{}{
+		{
 			"device":      "sensor1",
 			"temperature": 68.0, // 华氏度
 			"radius":      5.0,
 			"x1":          0.0, "y1": 0.0, "x2": 3.0, "y2": 4.0, // 距离=5
 		},
-		map[string]interface{}{
+		{
 			"device":      "sensor1",
 			"temperature": 86.0, // 华氏度
 			"radius":      10.0,
@@ -625,7 +625,7 @@ func testMathFunctions(ssql *streamsql.Streamsql) {
 	}
 
 	// 添加结果监听器
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  📊 数学函数结果: %v\n", result)
 	})
 
@@ -659,20 +659,20 @@ func testStringFunctions(ssql *streamsql.Streamsql) {
 	}
 
 	// 添加测试数据
-	testData := []interface{}{
+	testData := []map[string]interface{}{
-		map[string]interface{}{
+		{
 			"device":   "sensor1",
 			"metadata": `{"version":"1.0","type":"temperature"}`,
 			"level":    3,
 		},
-		map[string]interface{}{
+		{
 			"device":   "sensor2",
 			"metadata": `{"version":"2.0","type":"humidity"}`,
 			"level":    5,
 		},
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  📊 字符串函数结果: %v\n", result)
 	})
 
@@ -702,20 +702,20 @@ func testConversionFunctions(ssql *streamsql.Streamsql) {
 	}
 
 	// 添加测试数据
-	testData := []interface{}{
+	testData := []map[string]interface{}{
-		map[string]interface{}{
+		{
 			"device":       "server1",
 			"client_ip":    "192.168.1.100",
 			"memory_usage": 1073741824, // 1GB
 		},
-		map[string]interface{}{
+		{
 			"device":       "server2",
 			"client_ip":    "10.0.0.50",
 			"memory_usage": 2147483648, // 2GB
 		},
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  📊 转换函数结果: %v\n", result)
 	})
 
@@ -746,14 +746,14 @@ func testAggregateFunctions(ssql *streamsql.Streamsql) {
 	}
 
 	// 添加测试数据
-	testData := []interface{}{
+	testData := []map[string]interface{}{
-		map[string]interface{}{"device": "sensor1", "value": 2.0, "category": "A"},
+		{"device": "sensor1", "value": 2.0, "category": "A"},
-		map[string]interface{}{"device": "sensor1", "value": 8.0, "category": "A"},
+		{"device": "sensor1", "value": 8.0, "category": "A"},
-		map[string]interface{}{"device": "sensor1", "value": 32.0, "category": "B"},
+		{"device": "sensor1", "value": 32.0, "category": "B"},
-		map[string]interface{}{"device": "sensor1", "value": 128.0, "category": "A"},
+		{"device": "sensor1", "value": 128.0, "category": "A"},
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  📊 聚合函数结果: %v\n", result)
 	})
 

examples/nested-field-examples/main.go

@@ -119,19 +119,18 @@ func demonstrateBasicNestedAccess(ssql *streamsql.Streamsql) {
 	wg.Add(1)
 
 	// 设置结果回调
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		defer wg.Done()
 
 		fmt.Println("  📋 基础嵌套字段访问结果:")
-		if resultSlice, ok := result.([]map[string]interface{}); ok {
+		resultSlice := result
-			for i, item := range resultSlice {
+		for i, item := range resultSlice {
-				fmt.Printf("    记录 %d:\n", i+1)
+			fmt.Printf("    记录 %d:\n", i+1)
-				fmt.Printf("      设备名称: %v\n", item["device_name"])
+			fmt.Printf("      设备名称: %v\n", item["device_name"])
-				fmt.Printf("      设备位置: %v\n", item["device.location"])
+			fmt.Printf("      设备位置: %v\n", item["device.location"])
-				fmt.Printf("      温度: %v°C\n", item["sensor.temperature"])
+			fmt.Printf("      温度: %v°C\n", item["sensor.temperature"])
-				fmt.Printf("      湿度: %v%%\n", item["sensor.humidity"])
+			fmt.Printf("      湿度: %v%%\n", item["sensor.humidity"])
-				fmt.Println()
+			fmt.Println()
-			}
 		}
 	})
 
@@ -166,20 +165,19 @@ func demonstrateNestedAggregation(ssql *streamsql.Streamsql) {
 	wg.Add(1)
 
 	// 设置结果回调
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		defer wg.Done()
 
 		fmt.Println("  📈 嵌套字段聚合结果:")
-		if resultSlice, ok := result.([]map[string]interface{}); ok {
+		resultSlice := result
-			for i, item := range resultSlice {
+		for i, item := range resultSlice {
-				resultCount++
+			resultCount++
-				fmt.Printf("    聚合结果 %d:\n", i+1)
+			fmt.Printf("    聚合结果 %d:\n", i+1)
-				fmt.Printf("      位置: %v\n", item["device.location"])
+			fmt.Printf("      位置: %v\n", item["device.location"])
-				fmt.Printf("      平均温度: %.2f°C\n", item["avg_temp"])
+			fmt.Printf("      平均温度: %.2f°C\n", item["avg_temp"])
-				fmt.Printf("      最大湿度: %.1f%%\n", item["max_humidity"])
+			fmt.Printf("      最大湿度: %.1f%%\n", item["max_humidity"])
-				fmt.Printf("      传感器数量: %v\n", item["sensor_count"])
+			fmt.Printf("      传感器数量: %v\n", item["sensor_count"])
-				fmt.Println()
+			fmt.Println()
-			}
 		}
 	})
 
@@ -271,19 +269,18 @@ func demonstrateArrayAccess(ssql *streamsql.Streamsql) {
 	wg.Add(1)
 
 	// 设置结果回调
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		defer wg.Done()
 
 		fmt.Println("  📋 数组索引访问结果:")
-		if resultSlice, ok := result.([]map[string]interface{}); ok {
+		resultSlice := result
-			for i, item := range resultSlice {
+		for i, item := range resultSlice {
-				fmt.Printf("    记录 %d:\n", i+1)
+			fmt.Printf("    记录 %d:\n", i+1)
-				fmt.Printf("      设备: %v\n", item["device"])
+			fmt.Printf("      设备: %v\n", item["device"])
-				fmt.Printf("      第一个传感器温度: %v°C\n", item["first_sensor_temp"])
+			fmt.Printf("      第一个传感器温度: %v°C\n", item["first_sensor_temp"])
-				fmt.Printf("      第二个传感器湿度: %v%%\n", item["second_sensor_humidity"])
+			fmt.Printf("      第二个传感器湿度: %v%%\n", item["second_sensor_humidity"])
-				fmt.Printf("      第三个数据项: %v\n", item["third_data_item"])
+			fmt.Printf("      第三个数据项: %v\n", item["third_data_item"])
-				fmt.Println()
+			fmt.Println()
-			}
 		}
 	})
 
@@ -356,20 +353,19 @@ func demonstrateMapKeyAccess(ssql *streamsql.Streamsql) {
 	wg.Add(1)
 
 	// 设置结果回调
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		defer wg.Done()
 
 		fmt.Println("  🗝️ Map键访问结果:")
-		if resultSlice, ok := result.([]map[string]interface{}); ok {
+		resultSlice := result
-			for i, item := range resultSlice {
+		for i, item := range resultSlice {
-				fmt.Printf("    记录 %d:\n", i+1)
+			fmt.Printf("    记录 %d:\n", i+1)
-				fmt.Printf("      设备ID: %v\n", item["device_id"])
+			fmt.Printf("      设备ID: %v\n", item["device_id"])
-				fmt.Printf("      服务器主机: %v\n", item["server_host"])
+			fmt.Printf("      服务器主机: %v\n", item["server_host"])
-				fmt.Printf("      服务器端口: %v\n", item["server_port"])
+			fmt.Printf("      服务器端口: %v\n", item["server_port"])
-				fmt.Printf("      SSL启用: %v\n", item["ssl_enabled"])
+			fmt.Printf("      SSL启用: %v\n", item["ssl_enabled"])
-				fmt.Printf("      应用版本: %v\n", item["app_version"])
+			fmt.Printf("      应用版本: %v\n", item["app_version"])
-				fmt.Println()
+			fmt.Println()
-			}
 		}
 	})
 
@@ -454,20 +450,19 @@ func demonstrateComplexMixedAccess(ssql *streamsql.Streamsql) {
 	wg.Add(1)
 
 	// 设置结果回调
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		defer wg.Done()
 
 		fmt.Println("  🔄 混合复杂访问结果:")
-		if resultSlice, ok := result.([]map[string]interface{}); ok {
+		resultSlice := result
-			for i, item := range resultSlice {
+		for i, item := range resultSlice {
-				fmt.Printf("    记录 %d:\n", i+1)
+			fmt.Printf("    记录 %d:\n", i+1)
-				fmt.Printf("      建筑: %v\n", item["building"])
+			fmt.Printf("      建筑: %v\n", item["building"])
-				fmt.Printf("      一层第3个房间: %v\n", item["first_floor_room3_name"])
+			fmt.Printf("      一层第3个房间: %v\n", item["first_floor_room3_name"])
-				fmt.Printf("      二层第1个传感器温度: %v°C\n", item["second_floor_first_sensor_temp"])
+			fmt.Printf("      二层第1个传感器温度: %v°C\n", item["second_floor_first_sensor_temp"])
-				fmt.Printf("      建筑师: %v\n", item["building_architect"])
+			fmt.Printf("      建筑师: %v\n", item["building_architect"])
-				fmt.Printf("      最新警报: %v\n", item["latest_alert"])
+			fmt.Printf("      最新警报: %v\n", item["latest_alert"])
-				fmt.Println()
+			fmt.Println()
-			}
 		}
 	})
 
@@ -513,19 +508,18 @@ func demonstrateNegativeIndexAccess(ssql *streamsql.Streamsql) {
 	wg.Add(1)
 
 	// 设置结果回调
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		defer wg.Done()
 
 		fmt.Println("  ⬅️ 负数索引访问结果:")
-		if resultSlice, ok := result.([]map[string]interface{}); ok {
+		resultSlice := result
-			for i, item := range resultSlice {
+		for i, item := range resultSlice {
-				fmt.Printf("    记录 %d:\n", i+1)
+			fmt.Printf("    记录 %d:\n", i+1)
-				fmt.Printf("      设备名称: %v\n", item["device_name"])
+			fmt.Printf("      设备名称: %v\n", item["device_name"])
-				fmt.Printf("      最新读数: %v\n", item["latest_reading"])
+			fmt.Printf("      最新读数: %v\n", item["latest_reading"])
-				fmt.Printf("      倒数第二个事件: %v\n", item["second_last_event"])
+			fmt.Printf("      倒数第二个事件: %v\n", item["second_last_event"])
-				fmt.Printf("      最后一个标签: %v\n", item["last_tag"])
+			fmt.Printf("      最后一个标签: %v\n", item["last_tag"])
-				fmt.Println()
+			fmt.Println()
-			}
 		}
 	})
 
@@ -560,20 +554,19 @@ func demonstrateArrayIndexAggregation(ssql *streamsql.Streamsql) {
 	wg.Add(1)
 
 	// 设置结果回调
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		defer wg.Done()
 
 		fmt.Println("  📈 数组索引聚合计算结果:")
-		if resultSlice, ok := result.([]map[string]interface{}); ok {
+		resultSlice := result
-			for i, item := range resultSlice {
+		for i, item := range resultSlice {
-				resultCount++
+			resultCount++
-				fmt.Printf("    聚合结果 %d:\n", i+1)
+			fmt.Printf("    聚合结果 %d:\n", i+1)
-				fmt.Printf("      位置: %v\n", item["location"])
+			fmt.Printf("      位置: %v\n", item["location"])
-				fmt.Printf("      第一个传感器平均温度: %.2f°C\n", item["avg_first_sensor_temp"])
+			fmt.Printf("      第一个传感器平均温度: %.2f°C\n", item["avg_first_sensor_temp"])
-				fmt.Printf("      第二个传感器最大湿度: %.1f%%\n", item["max_second_sensor_humidity"])
+			fmt.Printf("      第二个传感器最大湿度: %.1f%%\n", item["max_second_sensor_humidity"])
-				fmt.Printf("      设备数量: %v\n", item["device_count"])
+			fmt.Printf("      设备数量: %v\n", item["device_count"])
-				fmt.Println()
+			fmt.Println()
-			}
 		}
 	})
 

examples/non-aggregation/main.go

@@ -62,7 +62,7 @@ func demonstrateDataCleaning() {
 	}
 
 	// 结果处理
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  清洗后数据: %+v\n", result)
 	})
 
@@ -103,7 +103,7 @@ func demonstrateDataEnrichment() {
 		panic(err)
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  富化后数据: %+v\n", result)
 	})
 
@@ -147,7 +147,7 @@ func demonstrateRealTimeAlerting() {
 		panic(err)
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  🚨 告警事件: %+v\n", result)
 	})
 
@@ -191,7 +191,7 @@ func demonstrateDataFormatConversion() {
 		panic(err)
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  格式转换结果: %+v\n", result)
 	})
 
@@ -230,7 +230,7 @@ func demonstrateDataRouting() {
 		panic(err)
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  路由结果: %+v\n", result)
 	})
 
@@ -273,7 +273,7 @@ func demonstrateNestedFieldProcessing() {
 		panic(err)
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  嵌套字段处理结果: %+v\n", result)
 	})
 

examples/null-comparison-examples/main.go

@@ -35,11 +35,9 @@ func demo1() {
 		panic(err)
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
-		if results, ok := result.([]map[string]interface{}); ok {
+		for _, data := range result {
-			for _, data := range results {
+			fmt.Printf("发现空值数据: %+v\n", data)
-				fmt.Printf("发现空值数据: %+v\n", data)
-			}
 		}
 	})
 
@@ -75,11 +73,9 @@ func demo2() {
 		panic(err)
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
-		if results, ok := result.([]map[string]interface{}); ok {
+		for _, data := range result {
-			for _, data := range results {
+			fmt.Printf("发现有效数据: %+v\n", data)
-				fmt.Printf("发现有效数据: %+v\n", data)
-			}
 		}
 	})
 
@@ -115,16 +111,14 @@ func demo3() {
 		panic(err)
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
-		if results, ok := result.([]map[string]interface{}); ok {
+		for _, data := range result {
-			for _, data := range results {
+			status := data["status"]
-				status := data["status"]
+			value := data["value"]
-				value := data["value"]
+			if status != nil {
-				if status != nil {
+				fmt.Printf("状态非空的数据: %+v\n", data)
-					fmt.Printf("状态非空的数据: %+v\n", data)
+			} else if value == nil {
-				} else if value == nil {
+				fmt.Printf("值为空的数据: %+v\n", data)
-					fmt.Printf("值为空的数据: %+v\n", data)
-				}
 			}
 		}
 	})
@@ -162,18 +156,16 @@ func demo4() {
 		panic(err)
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
-		if results, ok := result.([]map[string]interface{}); ok {
+		for _, data := range result {
-			for _, data := range results {
+			value := data["value"]
-				value := data["value"]
+			status := data["status"]
-				status := data["status"]
+			priority := data["priority"]
-				priority := data["priority"]
 
-				if value != nil && value.(float64) > 20 {
+			if value != nil && value.(float64) > 20 {
-					fmt.Printf("高值数据 (value > 20): %+v\n", data)
+				fmt.Printf("高值数据 (value > 20): %+v\n", data)
-				} else if status == nil && priority != nil {
+			} else if status == nil && priority != nil {
-					fmt.Printf("状态异常但有优先级的数据: %+v\n", data)
+				fmt.Printf("状态异常但有优先级的数据: %+v\n", data)
-				}
 			}
 		}
 	})
@@ -212,11 +204,9 @@ func demo5() {
 		panic(err)
 	}
 
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
-		if results, ok := result.([]map[string]interface{}); ok {
+		for _, data := range result {
-			for _, data := range results {
+			fmt.Printf("有位置信息的设备: %+v\n", data)
-				fmt.Printf("有位置信息的设备: %+v\n", data)
-			}
 		}
 	})
 

examples/persistence/main.go

@@ -1,233 +0,0 @@
-/*
- * Copyright 2025 The RuleGo Authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package main
-
-import (
-	"fmt"
-	"os"
-	"path/filepath"
-	"time"
-
-	"github.com/rulego/streamsql/stream"
-	"github.com/rulego/streamsql/types"
-)
-
-func main() {
-	fmt.Println("=== StreamSQL 持久化功能测试 ===")
-
-	// 清理之前的测试数据
-	cleanupTestData()
-
-	// 测试1: 创建持久化流并模拟数据溢出
-	fmt.Println("📌 测试1: 数据溢出持久化")
-	testDataOverflowPersistence()
-
-	// 测试2: 模拟程序重启和数据恢复
-	fmt.Println("📌 测试2: 程序重启数据恢复")
-	testDataRecovery()
-
-	// 测试3: 查看持久化文件内容
-	fmt.Println("📌 测试3: 持久化文件分析")
-	analyzePersistenceFiles()
-
-	fmt.Println("✅ 真正持久化功能测试完成！")
-}
-
-func testDataOverflowPersistence() {
-	config := types.Config{
-		SimpleFields: []string{"id", "value"},
-	}
-
-	// 创建小缓冲区的持久化流处理器
-	stream, err := stream.NewStreamWithLossPolicy(
-		config,
-		100,       // 很小的缓冲区，容易溢出
-		100,       // 小结果缓冲区
-		50,        // 小sink池
-		"persist", // 持久化策略
-		5*time.Second,
-	)
-	if err != nil {
-		fmt.Printf("创建流失败: %v\n", err)
-		return
-	}
-
-	stream.Start()
-
-	// 快速发送大量数据，触发溢出
-	inputCount := 1000
-	fmt.Printf("快速发送 %d 条数据到小缓冲区 (容量100)...\n", inputCount)
-
-	start := time.Now()
-	for i := 0; i < inputCount; i++ {
-		data := map[string]interface{}{
-			"id":    i,
-			"value": fmt.Sprintf("data_%d", i),
-		}
-		stream.Emit(data)
-	}
-	duration := time.Since(start)
-
-	// 等待持久化完成
-	fmt.Println("等待持久化操作完成...")
-	time.Sleep(8 * time.Second)
-
-	// 获取统计信息
-	stats := stream.GetDetailedStats()
-	persistStats := stream.GetPersistenceStats()
-
-	fmt.Printf("⏱️  发送耗时: %v\n", duration)
-	fmt.Printf("📊 输入数据: %d\n", stats["basic_stats"].(map[string]int64)["input_count"])
-	fmt.Printf("📊 处理数据: %d\n", stats["basic_stats"].(map[string]int64)["output_count"])
-	fmt.Printf("📊 通道容量: %d\n", stats["basic_stats"].(map[string]int64)["data_chan_cap"])
-	fmt.Printf("📊 持久化启用: %v\n", persistStats["enabled"])
-	fmt.Printf("📊 待写入数据: %v\n", persistStats["pending_count"])
-	fmt.Printf("📊 当前文件大小: %v bytes\n", persistStats["current_file_size"])
-	fmt.Printf("📊 文件索引: %v\n", persistStats["file_index"])
-
-	stream.Stop()
-}
-
-func testDataRecovery() {
-	config := types.Config{
-		SimpleFields: []string{"id", "value"},
-	}
-
-	// 创建新的持久化流处理器（模拟程序重启）
-	stream, err := stream.NewStreamWithLossPolicy(
-		config,
-		200, // 更大的缓冲区用于恢复
-		200,
-		100,
-		"persist", // 持久化策略
-		5*time.Second,
-	)
-	if err != nil {
-		fmt.Printf("创建流失败: %v\n", err)
-		return
-	}
-
-	stream.Start()
-
-	// 添加sink来接收恢复的数据
-	recoveredCount := 0
-	stream.AddSink(func(data interface{}) {
-		recoveredCount++
-		if recoveredCount <= 5 {
-			fmt.Printf("恢复数据 %d: %+v\n", recoveredCount, data)
-		}
-	})
-
-	// 尝试加载并重新处理持久化数据
-	fmt.Println("尝试加载持久化数据...")
-	if err := stream.LoadAndReprocessPersistedData(); err != nil {
-		fmt.Printf("数据恢复失败: %v\n", err)
-	}
-
-	// 等待处理完成
-	time.Sleep(3 * time.Second)
-
-	stats := stream.GetDetailedStats()
-	fmt.Printf("📊 恢复后处理数据: %d\n", stats["basic_stats"].(map[string]int64)["output_count"])
-	fmt.Printf("📊 接收到的恢复数据: %d\n", recoveredCount)
-
-	stream.Stop()
-}
-
-func analyzePersistenceFiles() {
-	dataDir := "./streamsql_overflow_data"
-
-	// 检查持久化目录
-	if _, err := os.Stat(dataDir); os.IsNotExist(err) {
-		fmt.Println("持久化目录不存在")
-		return
-	}
-
-	// 列出所有持久化文件
-	files, err := filepath.Glob(filepath.Join(dataDir, "streamsql_overflow_*.log"))
-	if err != nil {
-		fmt.Printf("读取持久化文件失败: %v\n", err)
-		return
-	}
-
-	if len(files) == 0 {
-		fmt.Println("没有找到持久化文件（可能已被恢复过程删除）")
-		return
-	}
-
-	fmt.Printf("发现 %d 个持久化文件:\n", len(files))
-	for i, file := range files {
-		info, err := os.Stat(file)
-		if err != nil {
-			fmt.Printf("  %d. %s (无法读取文件信息)\n", i+1, filepath.Base(file))
-			continue
-		}
-		fmt.Printf("  %d. %s (大小: %d bytes, 修改时间: %s)\n",
-			i+1, filepath.Base(file), info.Size(), info.ModTime().Format("15:04:05"))
-	}
-
-	// 读取第一个文件的前几行内容
-	if len(files) > 0 {
-		fmt.Printf("\n第一个文件的前3行内容:\n")
-		showFileContent(files[0], 3)
-	}
-}
-
-func showFileContent(filename string, maxLines int) {
-	file, err := os.Open(filename)
-	if err != nil {
-		fmt.Printf("无法打开文件: %v\n", err)
-		return
-	}
-	defer file.Close()
-
-	buffer := make([]byte, 1024)
-	n, err := file.Read(buffer)
-	if err != nil {
-		fmt.Printf("无法读取文件: %v\n", err)
-		return
-	}
-
-	content := string(buffer[:n])
-	lines := []rune(content)
-	lineCount := 0
-	currentLine := ""
-
-	for _, char := range lines {
-		if char == '\n' {
-			lineCount++
-			fmt.Printf("  %d: %s\n", lineCount, currentLine)
-			currentLine = ""
-			if lineCount >= maxLines {
-				break
-			}
-		} else {
-			currentLine += string(char)
-		}
-	}
-
-	if currentLine != "" && lineCount < maxLines {
-		fmt.Printf("  %d: %s\n", lineCount+1, currentLine)
-	}
-}
-
-func cleanupTestData() {
-	dataDir := "./streamsql_overflow_data"
-	if err := os.RemoveAll(dataDir); err != nil {
-		fmt.Printf("清理测试数据失败: %v\n", err)
-	}
-}

examples/simple-custom-functions/main.go

@@ -122,19 +122,19 @@ func testSimpleQuery(ssql *streamsql.Streamsql) {
 	}
 
 	// 添加结果监听器
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  📊 简单查询结果: %v\n", result)
 	})
 
 	// 添加测试数据
-	testData := []interface{}{
+	testData := []map[string]interface{}{
-		map[string]interface{}{
+		{
 			"device":      "sensor1",
 			"value":       5.0,
 			"temperature": 68.0, // 华氏度
 			"radius":      3.0,
 		},
-		map[string]interface{}{
+		{
 			"device":      "sensor2",
 			"value":       10.0,
 			"temperature": 86.0, // 华氏度
@@ -171,25 +171,25 @@ func testAggregateQuery(ssql *streamsql.Streamsql) {
 	}
 
 	// 添加结果监听器
-	ssql.AddSink(func(result interface{}) {
+	ssql.AddSink(func(result []map[string]interface{}) {
 		fmt.Printf("  📊 聚合查询结果: %v\n", result)
 	})
 
 	// 添加测试数据
-	testData := []interface{}{
+	testData := []map[string]interface{}{
-		map[string]interface{}{
+		{
 			"device":      "sensor1",
 			"value":       3.0,
 			"temperature": 32.0, // 0°C
 			"radius":      1.0,
 		},
-		map[string]interface{}{
+		{
 			"device":      "sensor1",
 			"value":       4.0,
 			"temperature": 212.0, // 100°C
 			"radius":      2.0,
 		},
-		map[string]interface{}{
+		{
 			"device":      "sensor2",
 			"value":       5.0,
 			"temperature": 68.0, // 20°C

examples/unified_config/demo.go

@@ -1,218 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"log"
-	"strings"
-	"time"
-
-	"github.com/rulego/streamsql/stream"
-	"github.com/rulego/streamsql/types"
-)
-
-func main() {
-	fmt.Println("=== StreamSQL 统一配置系统演示 ===")
-
-	// 1. 使用新的配置API创建默认配置Stream
-	fmt.Println("\n1. 默认配置Stream:")
-	defaultConfig := types.NewConfig()
-	defaultConfig.SimpleFields = []string{"temperature", "humidity", "location"}
-
-	defaultStream, err := stream.NewStream(defaultConfig)
-	if err != nil {
-		log.Fatal(err)
-	}
-	printStreamStats("默认配置", defaultStream)
-
-	// 2. 使用高性能预设配置
-	fmt.Println("\n2. 高性能配置Stream:")
-	highPerfConfig := types.NewConfigWithPerformance(types.HighPerformanceConfig())
-	highPerfConfig.SimpleFields = []string{"temperature", "humidity", "location"}
-
-	highPerfStream, err := stream.NewStreamWithHighPerformance(highPerfConfig)
-	if err != nil {
-		log.Fatal(err)
-	}
-	printStreamStats("高性能配置", highPerfStream)
-
-	// 3. 使用低延迟预设配置
-	fmt.Println("\n3. 低延迟配置Stream:")
-	lowLatencyConfig := types.NewConfigWithPerformance(types.LowLatencyConfig())
-	lowLatencyConfig.SimpleFields = []string{"temperature", "humidity", "location"}
-
-	lowLatencyStream, err := stream.NewStreamWithLowLatency(lowLatencyConfig)
-	if err != nil {
-		log.Fatal(err)
-	}
-	printStreamStats("低延迟配置", lowLatencyStream)
-
-	// 4. 使用零数据丢失预设配置
-	fmt.Println("\n4. 零数据丢失配置Stream:")
-	zeroLossConfig := types.NewConfigWithPerformance(types.ZeroDataLossConfig())
-	zeroLossConfig.SimpleFields = []string{"temperature", "humidity", "location"}
-
-	zeroLossStream, err := stream.NewStreamWithZeroDataLoss(zeroLossConfig)
-	if err != nil {
-		log.Fatal(err)
-	}
-	printStreamStats("零数据丢失配置", zeroLossStream)
-
-	// 5. 使用持久化预设配置
-	fmt.Println("\n5. 持久化配置Stream:")
-	persistConfig := types.NewConfigWithPerformance(types.PersistencePerformanceConfig())
-	persistConfig.SimpleFields = []string{"temperature", "humidity", "location"}
-
-	persistStream, err := stream.NewStreamWithCustomPerformance(persistConfig, types.PersistencePerformanceConfig())
-	if err != nil {
-		log.Fatal(err)
-	}
-	printStreamStats("持久化配置", persistStream)
-
-	// 6. 创建完全自定义的配置
-	fmt.Println("\n6. 自定义配置Stream:")
-	customPerfConfig := types.PerformanceConfig{
-		BufferConfig: types.BufferConfig{
-			DataChannelSize:     30000,
-			ResultChannelSize:   25000,
-			WindowOutputSize:    3000,
-			EnableDynamicResize: true,
-			MaxBufferSize:       200000,
-			UsageThreshold:      0.85,
-		},
-		OverflowConfig: types.OverflowConfig{
-			Strategy:      "expand",
-			BlockTimeout:  15 * time.Second,
-			AllowDataLoss: false,
-			ExpansionConfig: types.ExpansionConfig{
-				GrowthFactor:     2.0,
-				MinIncrement:     2000,
-				TriggerThreshold: 0.9,
-				ExpansionTimeout: 3 * time.Second,
-			},
-		},
-		WorkerConfig: types.WorkerConfig{
-			SinkPoolSize:     800,
-			SinkWorkerCount:  12,
-			MaxRetryRoutines: 10,
-		},
-		MonitoringConfig: types.MonitoringConfig{
-			EnableMonitoring:    true,
-			StatsUpdateInterval: 500 * time.Millisecond,
-			EnableDetailedStats: true,
-			WarningThresholds: types.WarningThresholds{
-				DropRateWarning:     5.0,
-				DropRateCritical:    15.0,
-				BufferUsageWarning:  75.0,
-				BufferUsageCritical: 90.0,
-			},
-		},
-	}
-
-	customConfig := types.NewConfigWithPerformance(customPerfConfig)
-	customConfig.SimpleFields = []string{"temperature", "humidity", "location"}
-
-	customStream, err := stream.NewStreamWithCustomPerformance(customConfig, customPerfConfig)
-	if err != nil {
-		log.Fatal(err)
-	}
-	printStreamStats("自定义配置", customStream)
-
-	// 7. 配置比较演示
-	fmt.Println("\n7. 配置比较:")
-	compareConfigurations()
-
-	// 8. 实时数据处理演示
-	fmt.Println("\n8. 实时数据处理演示:")
-	demonstrateRealTimeProcessing(defaultStream)
-
-	// 9. 窗口统一配置演示
-	fmt.Println("\n9. 窗口统一配置演示:")
-	demonstrateWindowConfig()
-
-	// 清理资源
-	fmt.Println("\n10. 清理资源...")
-	defaultStream.Stop()
-	highPerfStream.Stop()
-	lowLatencyStream.Stop()
-	zeroLossStream.Stop()
-	persistStream.Stop()
-	customStream.Stop()
-
-	fmt.Println("\n=== 演示完成 ===")
-}
-
-func printStreamStats(name string, s *stream.Stream) {
-	stats := s.GetStats()
-	detailedStats := s.GetDetailedStats()
-
-	fmt.Printf("【%s】统计信息:\n", name)
-	fmt.Printf("  数据通道: %d/%d (使用率: %.1f%%)\n",
-		stats["data_chan_len"], stats["data_chan_cap"],
-		detailedStats["data_chan_usage"])
-	fmt.Printf("  结果通道: %d/%d (使用率: %.1f%%)\n",
-		stats["result_chan_len"], stats["result_chan_cap"],
-		detailedStats["result_chan_usage"])
-	fmt.Printf("  工作池: %d/%d (使用率: %.1f%%)\n",
-		stats["sink_pool_len"], stats["sink_pool_cap"],
-		detailedStats["sink_pool_usage"])
-	fmt.Printf("  性能等级: %s\n", detailedStats["performance_level"])
-}
-
-func compareConfigurations() {
-	configs := map[string]types.PerformanceConfig{
-		"默认配置":  types.DefaultPerformanceConfig(),
-		"高性能配置": types.HighPerformanceConfig(),
-		"低延迟配置": types.LowLatencyConfig(),
-		"零丢失配置": types.ZeroDataLossConfig(),
-		"持久化配置": types.PersistencePerformanceConfig(),
-	}
-
-	fmt.Printf("%-12s %-10s %-10s %-10s %-10s %-15s\n",
-		"配置类型", "数据缓冲", "结果缓冲", "工作池", "工作线程", "溢出策略")
-	fmt.Println(strings.Repeat("-", 75))
-
-	for name, config := range configs {
-		fmt.Printf("%-12s %-10d %-10d %-10d %-10d %-15s\n",
-			name,
-			config.BufferConfig.DataChannelSize,
-			config.BufferConfig.ResultChannelSize,
-			config.WorkerConfig.SinkPoolSize,
-			config.WorkerConfig.SinkWorkerCount,
-			config.OverflowConfig.Strategy)
-	}
-}
-
-func demonstrateRealTimeProcessing(s *stream.Stream) {
-	// 设置数据接收器
-	s.AddSink(func(data interface{}) {
-		fmt.Printf("  接收到处理结果: %v\n", data)
-	})
-
-	// 启动流处理
-	s.Start()
-
-	// 模拟发送数据
-	for i := 0; i < 3; i++ {
-		data := map[string]interface{}{
-			"temperature": 20.0 + float64(i)*2.5,
-			"humidity":    60.0 + float64(i)*5,
-			"location":    fmt.Sprintf("sensor_%d", i+1),
-			"timestamp":   time.Now().Unix(),
-		}
-
-		fmt.Printf("  发送数据: %v\n", data)
-		s.Emit(data)
-		time.Sleep(100 * time.Millisecond)
-	}
-
-	// 等待处理完成
-	time.Sleep(200 * time.Millisecond)
-
-	// 显示最终统计
-	finalStats := s.GetDetailedStats()
-	fmt.Printf("  最终统计 - 输入: %d, 输出: %d, 丢弃: %d, 处理率: %.1f%%\n",
-		finalStats["basic_stats"].(map[string]int64)["input_count"],
-		finalStats["basic_stats"].(map[string]int64)["output_count"],
-		finalStats["basic_stats"].(map[string]int64)["dropped_count"],
-		finalStats["process_rate"])
-}

examples/unified_config/window_config_demo.go

@@ -1,74 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"time"
-
-	"github.com/rulego/streamsql"
-	"github.com/rulego/streamsql/types"
-)
-
-// demonstrateWindowConfig 演示窗口统一配置的使用
-func demonstrateWindowConfig() {
-	fmt.Println("=== 窗口统一配置演示 ===")
-
-	// 1. 测试默认配置的窗口
-	fmt.Println("\n1. 默认配置窗口测试")
-	testWindowWithConfig("默认配置", streamsql.New())
-
-	// 2. 测试高性能配置的窗口
-	fmt.Println("\n2. 高性能配置窗口测试")
-	testWindowWithConfig("高性能配置", streamsql.New(streamsql.WithHighPerformance()))
-
-	// 3. 测试低延迟配置的窗口
-	fmt.Println("\n3. 低延迟配置窗口测试")
-	testWindowWithConfig("低延迟配置", streamsql.New(streamsql.WithLowLatency()))
-
-	// 4. 测试自定义配置的窗口
-	fmt.Println("\n4. 自定义配置窗口测试")
-	customConfig := types.DefaultPerformanceConfig()
-	customConfig.BufferConfig.WindowOutputSize = 2000 // 自定义窗口输出缓冲区大小
-	testWindowWithConfig("自定义配置", streamsql.New(streamsql.WithCustomPerformance(customConfig)))
-
-	fmt.Println("\n=== 窗口配置演示完成 ===")
-}
-
-func testWindowWithConfig(configName string, ssql *streamsql.Streamsql) {
-	// 执行一个简单的滚动窗口查询
-	sql := "SELECT deviceId, AVG(temperature) as avg_temp FROM stream GROUP BY deviceId, TumblingWindow('2s')"
-
-	err := ssql.Execute(sql)
-	if err != nil {
-		fmt.Printf("❌ %s - 执行SQL失败: %v\n", configName, err)
-		return
-	}
-
-	// 添加结果处理器
-	stream := ssql.Stream()
-	if stream != nil {
-		stream.AddSink(func(result interface{}) {
-			fmt.Printf("📊 %s - 窗口结果: %v\n", configName, result)
-		})
-
-		// 发送测试数据
-		for i := 0; i < 5; i++ {
-			data := map[string]interface{}{
-				"deviceId":    fmt.Sprintf("device_%d", i%2),
-				"temperature": 20.0 + float64(i),
-				"timestamp":   time.Now(),
-			}
-			ssql.Emit(data)
-		}
-
-		// 等待处理完成
-		time.Sleep(3 * time.Second)
-
-		// 获取统计信息
-		stats := ssql.GetDetailedStats()
-		fmt.Printf("📈 %s - 统计信息: %v\n", configName, stats)
-	}
-
-	// 停止流处理
-	ssql.Stop()
-	fmt.Printf("✅ %s - 测试完成\n", configName)
-}

expr/case_expression.go

@@ -0,0 +1,245 @@
+package expr
+
+import (
+	"fmt"
+	"strings"
+)
+
+// parseCaseExpression parses CASE expression
+func parseCaseExpression(tokens []string) (*ExprNode, []string, error) {
+	if len(tokens) == 0 || strings.ToUpper(tokens[0]) != "CASE" {
+		return nil, nil, fmt.Errorf("expected CASE keyword")
+	}
+
+	remaining := tokens[1:]
+	caseExpr := &CaseExpression{}
+
+	// Check if it's a simple CASE expression (CASE expr WHEN value THEN result)
+	if len(remaining) > 0 && strings.ToUpper(remaining[0]) != "WHEN" {
+		// Simple CASE expression
+		value, newRemaining, err := parseOrExpression(remaining)
+		if err != nil {
+			return nil, nil, fmt.Errorf("error parsing CASE expression: %v", err)
+		}
+		caseExpr.Value = value
+		remaining = newRemaining
+	}
+
+	// Parse WHEN clauses
+	for len(remaining) > 0 && strings.ToUpper(remaining[0]) == "WHEN" {
+		remaining = remaining[1:] // Skip WHEN
+
+		// Parse WHEN condition
+		condition, newRemaining, err := parseOrExpression(remaining)
+		if err != nil {
+			return nil, nil, fmt.Errorf("error parsing WHEN condition: %v", err)
+		}
+		remaining = newRemaining
+
+		// Check THEN keyword
+		if len(remaining) == 0 || strings.ToUpper(remaining[0]) != "THEN" {
+			return nil, nil, fmt.Errorf("expected THEN after WHEN condition")
+		}
+		remaining = remaining[1:] // Skip THEN
+
+		// Parse THEN result
+		result, newRemaining, err := parseOrExpression(remaining)
+		if err != nil {
+			return nil, nil, fmt.Errorf("error parsing THEN result: %v", err)
+		}
+		remaining = newRemaining
+
+		// Add WHEN clause
+		caseExpr.WhenClauses = append(caseExpr.WhenClauses, WhenClause{
+			Condition: condition,
+			Result:    result,
+		})
+	}
+
+	// Parse optional ELSE clause
+	if len(remaining) > 0 && strings.ToUpper(remaining[0]) == "ELSE" {
+		remaining = remaining[1:] // Skip ELSE
+
+		elseExpr, newRemaining, err := parseOrExpression(remaining)
+		if err != nil {
+			return nil, nil, fmt.Errorf("error parsing ELSE expression: %v", err)
+		}
+		caseExpr.ElseResult = elseExpr
+		remaining = newRemaining
+	}
+
+	// Check END keyword
+	if len(remaining) == 0 || strings.ToUpper(remaining[0]) != "END" {
+		return nil, nil, fmt.Errorf("expected END to close CASE expression")
+	}
+
+	// Create ExprNode containing CaseExpression
+	caseNode := &ExprNode{
+		Type:     TypeCase,
+		CaseExpr: caseExpr,
+	}
+
+	return caseNode, remaining[1:], nil
+}
+
+// evaluateCaseExpression evaluates the value of CASE expression
+func evaluateCaseExpression(node *ExprNode, data map[string]interface{}) (float64, error) {
+	if node.Type != TypeCase {
+		return 0, fmt.Errorf("not a CASE expression")
+	}
+
+	if node.CaseExpr == nil {
+		return 0, fmt.Errorf("invalid CASE expression")
+	}
+
+	// Simple CASE expression: CASE expr WHEN value THEN result
+	if node.CaseExpr.Value != nil {
+		return evaluateSimpleCaseExpression(node, data)
+	}
+
+	// Search CASE expression: CASE WHEN condition THEN result
+	return evaluateSearchCaseExpression(node, data)
+}
+
+// evaluateSimpleCaseExpression evaluates simple CASE expression
+func evaluateSimpleCaseExpression(node *ExprNode, data map[string]interface{}) (float64, error) {
+	caseExpr := node.CaseExpr
+	if caseExpr == nil {
+		return 0, fmt.Errorf("invalid CASE expression")
+	}
+
+	// Evaluate CASE expression value
+	caseValue, err := evaluateNodeValue(caseExpr.Value, data)
+	if err != nil {
+		return 0, err
+	}
+
+	// Iterate through WHEN clauses
+	for _, whenClause := range caseExpr.WhenClauses {
+		// Evaluate WHEN value
+		whenValue, err := evaluateNodeValue(whenClause.Condition, data)
+		if err != nil {
+			return 0, err
+		}
+
+		// Compare values
+		if compareValuesForEquality(caseValue, whenValue) {
+			// Evaluate and return THEN result
+			return evaluateNode(whenClause.Result, data)
+		}
+	}
+
+	// If no matching WHEN clause, evaluate ELSE expression
+	if caseExpr.ElseResult != nil {
+		return evaluateNode(caseExpr.ElseResult, data)
+	}
+
+	// If no ELSE clause, return NULL (return 0 here)
+	return 0, nil
+}
+
+// evaluateSearchCaseExpression evaluates search CASE expression
+func evaluateSearchCaseExpression(node *ExprNode, data map[string]interface{}) (float64, error) {
+	caseExpr := node.CaseExpr
+	if caseExpr == nil {
+		return 0, fmt.Errorf("invalid CASE expression")
+	}
+
+	// Iterate through WHEN clauses
+	for _, whenClause := range caseExpr.WhenClauses {
+		// Evaluate WHEN condition - use boolean evaluation to handle logical operators
+		conditionResult, err := evaluateBoolNode(whenClause.Condition, data)
+		if err != nil {
+			return 0, err
+		}
+
+		// If condition is true, return THEN result
+		if conditionResult {
+			return evaluateNode(whenClause.Result, data)
+		}
+	}
+
+	// If no matching WHEN clause, evaluate ELSE expression
+	if caseExpr.ElseResult != nil {
+		return evaluateNode(caseExpr.ElseResult, data)
+	}
+
+	// If no ELSE clause, return NULL (return 0 here)
+	return 0, nil
+}
+
+// evaluateCaseExpressionWithNull evaluates CASE expression with NULL value support
+func evaluateCaseExpressionWithNull(node *ExprNode, data map[string]interface{}) (interface{}, bool, error) {
+	if node.Type != TypeCase {
+		return nil, false, fmt.Errorf("not a CASE expression")
+	}
+
+	caseExpr := node.CaseExpr
+	if caseExpr == nil {
+		return nil, false, fmt.Errorf("invalid CASE expression")
+	}
+
+	// Simple CASE expression: CASE expr WHEN value THEN result
+	if caseExpr.Value != nil {
+		return evaluateCaseExpressionValueWithNull(node, data)
+	}
+
+	// Search CASE expression: CASE WHEN condition THEN result
+	for _, whenClause := range caseExpr.WhenClauses {
+		// Evaluate WHEN condition - use boolean evaluation to handle logical operators
+		conditionResult, err := evaluateBoolNode(whenClause.Condition, data)
+		if err != nil {
+			return nil, false, err
+		}
+
+		// If condition is true, return THEN result
+		if conditionResult {
+			return evaluateNodeValueWithNull(whenClause.Result, data)
+		}
+	}
+
+	// If no matching WHEN clause, evaluate ELSE expression
+	if caseExpr.ElseResult != nil {
+		return evaluateNodeValueWithNull(caseExpr.ElseResult, data)
+	}
+
+	// If no ELSE clause, return NULL
+	return nil, true, nil
+}
+
+// evaluateCaseExpressionValueWithNull evaluates simple CASE expression (with NULL support)
+func evaluateCaseExpressionValueWithNull(node *ExprNode, data map[string]interface{}) (interface{}, bool, error) {
+	caseExpr := node.CaseExpr
+	if caseExpr == nil {
+		return nil, false, fmt.Errorf("invalid CASE expression")
+	}
+
+	// Evaluate CASE expression value
+	caseValue, caseIsNull, err := evaluateNodeValueWithNull(caseExpr.Value, data)
+	if err != nil {
+		return nil, false, err
+	}
+
+	// Iterate through WHEN clauses
+	for _, whenClause := range caseExpr.WhenClauses {
+		// Evaluate WHEN value
+		whenValue, whenIsNull, err := evaluateNodeValueWithNull(whenClause.Condition, data)
+		if err != nil {
+			return nil, false, err
+		}
+
+		// Compare values (with NULL comparison support)
+		if compareValuesWithNullForEquality(caseValue, caseIsNull, whenValue, whenIsNull) {
+			// Evaluate and return THEN result
+			return evaluateNodeValueWithNull(whenClause.Result, data)
+		}
+	}
+
+	// If no matching WHEN clause, evaluate ELSE expression
+	if caseExpr.ElseResult != nil {
+		return evaluateNodeValueWithNull(caseExpr.ElseResult, data)
+	}
+
+	// If no ELSE clause, return NULL
+	return nil, true, nil
+}

expr/doc.go

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2025 The RuleGo Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+Package expr provides expression parsing and evaluation capabilities for StreamSQL.
+
+This package implements a comprehensive expression engine that supports mathematical operations,
+logical comparisons, function calls, field references, and complex CASE expressions.
+It serves as the foundation for WHERE clauses, HAVING clauses, and computed fields in SQL queries.
+
+# Core Features
+
+• Mathematical Operations - Supports arithmetic operators (+, -, *, /, %, ^) with proper precedence
+• Logical Operations - Boolean logic with AND, OR operators and comparison operators (=, !=, <, >, <=, >=, LIKE)
+• Function Integration - Seamless integration with the functions package for built-in and custom functions
+• Field References - Dynamic field access with dot notation support for nested data structures
+• CASE Expressions - Full support for both simple and searched CASE expressions
+• Type Safety - Automatic type conversion and validation during expression evaluation
+• Fallback Support - Integration with expr-lang/expr library for complex expressions
+
+# Expression Types
+
+The package supports various expression node types:
+
+	// Basic types
+	TypeNumber      - Numeric constants (integers and floats)
+	TypeString      - String literals with proper escaping
+	TypeField       - Field references (e.g., "temperature", "device.id")
+	TypeOperator    - Binary and unary operators
+	TypeFunction    - Function calls with argument validation
+	TypeParenthesis - Grouped expressions for precedence control
+	TypeCase        - CASE expressions for conditional logic
+
+# Usage Examples
+
+Basic mathematical expression:
+
+	expr, err := NewExpression("temperature * 1.8 + 32")
+	if err != nil {
+		log.Fatal(err)
+	}
+	result, err := expr.Evaluate(data)
+
+Logical expression with field references:
+
+	expr, err := NewExpression("temperature > 25 AND humidity < 60")
+	result, err := expr.Evaluate(data)
+
+Function call expression:
+
+	expr, err := NewExpression("UPPER(device_name) LIKE 'SENSOR%'")
+	result, err := expr.Evaluate(data)
+
+CASE expression for conditional logic:
+
+	expr, err := NewExpression(`
+		CASE
+			WHEN temperature > 30 THEN 'hot'
+			WHEN temperature > 20 THEN 'warm'
+			ELSE 'cold'
+		END
+	`)
+	result, err := expr.Evaluate(data)
+
+# Operator Precedence
+
+The expression parser follows standard mathematical precedence rules:
+
+ 1. Parentheses (highest)
+ 2. Power (^)
+ 3. Multiplication, Division, Modulo (*, /, %)
+ 4. Addition, Subtraction (+, -)
+ 5. Comparison (>, <, >=, <=, LIKE, IS)
+ 6. Equality (=, ==, !=, <>)
+ 7. Logical AND
+ 8. Logical OR (lowest)
+
+# Error Handling
+
+The package provides comprehensive error handling with detailed error messages:
+
+• Syntax validation during expression creation
+• Type checking during evaluation
+• Function argument validation
+• Graceful fallback to expr-lang for unsupported expressions
+
+# Performance Considerations
+
+• Expressions are parsed once and can be evaluated multiple times
+• Built-in operator optimization for common mathematical operations
+• Lazy evaluation for logical operators (short-circuiting)
+• Efficient field access caching for repeated evaluations
+• Automatic fallback to optimized expr-lang library when needed
+
+# Integration
+
+This package integrates seamlessly with other StreamSQL components:
+
+• Functions package - For built-in and custom function execution
+• Types package - For data type definitions and conversions
+• Stream package - For real-time expression evaluation in data streams
+• RSQL package - For SQL parsing and expression extraction
+*/
+package expr