mirror of
https://gitee.com/rulego/streamsql.git
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109 lines
2.6 KiB
Go
109 lines
2.6 KiB
Go
package functions
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import (
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"fmt"
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"reflect"
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)
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// UnnestFunction 将数组展开为多行
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type UnnestFunction struct {
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*BaseFunction
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}
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func NewUnnestFunction() *UnnestFunction {
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return &UnnestFunction{
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BaseFunction: NewBaseFunction("unnest", TypeString, "多行函数", "将数组展开为多行", 1, 1),
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}
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}
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func (f *UnnestFunction) Validate(args []interface{}) error {
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return f.ValidateArgCount(args)
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}
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func (f *UnnestFunction) Execute(ctx *FunctionContext, args []interface{}) (interface{}, error) {
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if err := f.Validate(args); err != nil {
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return nil, err
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}
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array := args[0]
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if array == nil {
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return []interface{}{}, nil
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}
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// 使用反射检查是否为数组或切片
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v := reflect.ValueOf(array)
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if v.Kind() != reflect.Slice && v.Kind() != reflect.Array {
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return nil, fmt.Errorf("unnest requires an array or slice, got %T", array)
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}
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// 转换为 []interface{}
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result := make([]interface{}, v.Len())
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for i := 0; i < v.Len(); i++ {
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elem := v.Index(i).Interface()
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// 如果数组元素是对象（map），则展开为列
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if elemMap, ok := elem.(map[string]interface{}); ok {
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// 对于对象，我们返回一个特殊的结构来表示需要展开为列
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result[i] = map[string]interface{}{
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"__unnest_object__": true,
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"__data__": elemMap,
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}
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} else {
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result[i] = elem
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}
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}
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return result, nil
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}
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// UnnestResult 表示 unnest 函数的结果
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type UnnestResult struct {
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Rows []map[string]interface{}
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}
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// IsUnnestResult 检查是否为 unnest 结果
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func IsUnnestResult(value interface{}) bool {
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if slice, ok := value.([]interface{}); ok {
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for _, item := range slice {
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if itemMap, ok := item.(map[string]interface{}); ok {
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if unnest, exists := itemMap["__unnest_object__"]; exists {
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if unnestBool, ok := unnest.(bool); ok && unnestBool {
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return true
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}
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}
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}
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}
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}
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return false
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}
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// ProcessUnnestResult 处理 unnest 结果，将其转换为多行
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func ProcessUnnestResult(value interface{}) []map[string]interface{} {
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slice, ok := value.([]interface{})
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if !ok {
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return nil
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}
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var rows []map[string]interface{}
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for _, item := range slice {
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if itemMap, ok := item.(map[string]interface{}); ok {
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if unnest, exists := itemMap["__unnest_object__"]; exists {
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if unnestBool, ok := unnest.(bool); ok && unnestBool {
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if data, exists := itemMap["__data__"]; exists {
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if dataMap, ok := data.(map[string]interface{}); ok {
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rows = append(rows, dataMap)
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}
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}
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continue
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}
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}
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}
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// 对于非对象元素，创建一个包含单个值的行
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row := map[string]interface{}{
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"value": item,
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}
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rows = append(rows, row)
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}
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return rows
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} |