feat: Introduce allowUnparenthesizedSubSelects feature

JSQLParser · manticore-projects · Aug 20, 2024 · Jul 22, 2024 · Jul 22, 2024 · Jul 23, 2024
commit 345ec1be05b58d75e9a54ae1e18c2f96e4c6ec08
diff --git a/src/main/java/net/sf/jsqlparser/parser/AbstractJSqlParser.java b/src/main/java/net/sf/jsqlparser/parser/AbstractJSqlParser.java
@@ -65,6 +65,14 @@ public P withBackslashEscapeCharacter(boolean allowBackslashEscapeCharacter) {
         return withFeature(Feature.allowBackslashEscapeCharacter, allowBackslashEscapeCharacter);
     }
 
+    public P withUnparenthesizedSubSelects() {
+        return withFeature(Feature.allowUnparenthesizedSubSelects, true);
+    }
+
+    public P withUnparenthesizedSubSelects(boolean allowUnparenthesizedSubSelects) {
+        return withFeature(Feature.allowUnparenthesizedSubSelects, allowUnparenthesizedSubSelects);
+    }
+
     public P withFeature(Feature f, boolean enabled) {
         getConfiguration().setValue(f, enabled);
         return me();

diff --git a/src/main/java/net/sf/jsqlparser/parser/feature/Feature.java b/src/main/java/net/sf/jsqlparser/parser/feature/Feature.java
@@ -787,6 +787,12 @@ public enum Feature {
      * allows Backslash '\' as Escape Character
      */
     allowBackslashEscapeCharacter(false),
+
+    /**
+     * allows sub selects without parentheses, e.g.
+     * `select * from dual where 1 = select 1`
+     */
+    allowUnparenthesizedSubSelects(false),
     ;
 
     private final Object value;

diff --git a/src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt b/src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt
@@ -4527,9 +4527,9 @@ Expression PrimaryExpression() #PrimaryExpression:
 
         | "{ts" token=<S_CHAR_LITERAL> "}" { retval = new TimestampValue(token.image); }
 
-        | LOOKAHEAD( ParenthesedSelect() , {!interrupted} ) retval=ParenthesedSelect()
+        | LOOKAHEAD( Select() , { getAsBoolean(Feature.allowUnparenthesizedSubSelects) && !interrupted } ) retval=Select()
 
-        | LOOKAHEAD( Select() , {!interrupted} ) retval=Select()
+        | LOOKAHEAD( ParenthesedSelect() , { !getAsBoolean(Feature.allowUnparenthesizedSubSelects) && !interrupted } ) retval=ParenthesedSelect()
 
         |
         (
@@ -5619,7 +5619,7 @@ Function InternalFunction(boolean escaped):
         (
             LOOKAHEAD(3) expressionList=ExpressionList() [ orderByList = OrderByElements() { retval.setOrderByElements(orderByList); } ]
             |
-            expr = Select() { expressionList = new ExpressionList(expr); }
+            LOOKAHEAD({ !getAsBoolean(Feature.allowUnparenthesizedSubSelects) }) expr = Select() { expressionList = new ExpressionList(expr); }
         )
     ]
 

diff --git a/src/test/java/net/sf/jsqlparser/expression/FunctionTest.java b/src/test/java/net/sf/jsqlparser/expression/FunctionTest.java
@@ -79,6 +79,7 @@ void testSubSelectArrayWithoutKeywordParameter() throws JSQLParserException {
     @Test
     void testSubSelectParameterWithoutParentheses() throws JSQLParserException {
         String sqlStr = "SELECT COALESCE(SELECT mycolumn FROM mytable, 0)";
-        TestUtils.assertSqlCanBeParsedAndDeparsed(sqlStr, true);
+        TestUtils.assertSqlCanBeParsedAndDeparsed(sqlStr, true,
+            parser -> parser.withUnparenthesizedSubSelects(true));
     }
 }
diff --git a/src/test/java/net/sf/jsqlparser/statement/select/SelectTest.java b/src/test/java/net/sf/jsqlparser/statement/select/SelectTest.java
@@ -5842,4 +5842,15 @@ void testGroupByWithHaving() throws JSQLParserException {
         Statement stmt = assertSqlCanBeParsedAndDeparsed(sqlStr);
         Assertions.assertInstanceOf(Select.class, stmt);
     }
+
+    @ParameterizedTest
+    @ValueSource(strings = {
+        "SELECT SELECT 1",
+        "SELECT 1 WHERE 1 = SELECT 1",
+        "SELECT 1 WHERE 1 IN SELECT 1"
+    })
+    public void testUnparenthesizedSubSelect(String sqlStr) throws JSQLParserException {
+        TestUtils.assertSqlCanBeParsedAndDeparsed(sqlStr, true,
+            parser -> parser.withUnparenthesizedSubSelects(true));
+    }
 }