[plsql] ParseException with subqueries in WHERE clause

Fixes #1589

docs/pages/release_notes.md

@@ -37,6 +37,8 @@ This is a {{ site.pmd.release_type }} release.
     *   [#1633](https://github.com/pmd/pmd/issues/1633): \[java] UnsynchronizedStaticFormatter reports commons lang FastDateFormat
 *   java-performance
     *   [#1632](https://github.com/pmd/pmd/issues/1632): \[java] ConsecutiveLiteralAppends false positive over catch
+*   plsql
+    *   [#1589](https://github.com/pmd/pmd/issues/1589): \[plsql] ParseException with subqueries in WHERE clause
 
 ### API Changes
 

pmd-plsql/etc/grammar/PldocAST.jjt

@@ -1414,6 +1414,8 @@ ASTSqlExpression SqlExpression() :
     LOOKAHEAD(2) Column()
  |
     LOOKAHEAD(2) <ROWNUM>
+ |
+    LOOKAHEAD(2) "(" SelectStatement() ")"  // see "Scalar Subquery Expressions"
  |
     AdditiveExpression() // this can be a literal or a simple expression, but no conditional
  )

pmd-plsql/src/test/java/net/sourceforge/pmd/lang/plsql/ast/WhereClauseTest.java

@@ -68,4 +68,11 @@ public class WhereClauseTest extends AbstractPLSQLParserTst {
                 StandardCharsets.UTF_8);
         ASTInput input = parsePLSQL(code);
     }
+
+    @Test
+    public void testSubqueries() throws Exception {
+        String code = IOUtils.toString(this.getClass().getResourceAsStream("WhereClauseSubqueries.pls"),
+                StandardCharsets.UTF_8);
+        ASTInput input = parsePLSQL(code);
+    }
 }

pmd-plsql/src/test/resources/net/sourceforge/pmd/lang/plsql/ast/WhereClauseSubqueries.pls

@@ -0,0 +1,14 @@
+--
+-- Where Clause with Subqueries
+--
+
+BEGIN
+
+SELECT id INTO v_id FROM table
+  WHERE id = (SELECT id FROM other_table);
+
+UPDATE table SET name = 'a'
+  WHERE id = (SELECT id FROM other_table);
+
+END;
+/