Support ORDER BY after IGNORE NULLS in aggregate functions

BigQuery orders aggregate arguments as
ARRAY_AGG(expr [IGNORE NULLS] [ORDER BY key] [LIMIT n]), so the ORDER BY
may follow the null handling. Only the pre-null-handling position was
accepted before.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EqinwHBKuAtPEmtXr3b5P2

Author: hayssams

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -11519,6 +11519,7 @@ Function InternalFunction(boolean escaped):
     Column attributeColumn = null;
     Token attributeToken = null;
     Limit limit;
+    List<OrderByElement> orderByList = null;
     List<Function.KeywordArgument> keywordArgs = null;
 }
 {
@@ -11568,6 +11569,12 @@ Function InternalFunction(boolean escaped):
         )
     ]
 
+    // BigQuery orders aggregate arguments after the null handling:
+    // ARRAY_AGG(expr [IGNORE NULLS] [ORDER BY key] [LIMIT n])
+    [
+        LOOKAHEAD(2) orderByList = OrderByElements() { retval.setOrderByElements(orderByList); }
+    ]
+
     [
         limit = PlainLimit() { retval.setLimit(limit); }
     ]
@@ -11651,7 +11658,8 @@ ExpressionList FunctionArgumentList(Function retval):
     { if ("XMLFOREST".equalsIgnoreCase(retval.getName())) { return XmlForestArguments(); } }
     [ LOOKAHEAD(2) extraKeywordToken = <K_TABLE> { retval.setExtraKeyword(extraKeywordToken.image); } ]
     expressionList=ExpressionList()
-    [ orderByList = OrderByElements() { retval.setOrderByElements(orderByList); } ]
+    // explicit lookahead: InternalFunction accepts ORDER BY after IGNORE NULLS too
+    [ LOOKAHEAD(2) orderByList = OrderByElements() { retval.setOrderByElements(orderByList); } ]
 
     // https://docs.oracle.com/en/database/oracle/oracle-database/21/sqlrf/LISTAGG.html
     [

src/test/java/net/sf/jsqlparser/statement/select/BigQueryTest.java

@@ -160,4 +160,22 @@ void testUnnestWithOrdinalityAliasStillBindsToTableFunction() throws JSQLParserE
         Assertions.assertFalse(unnest.isWithOffset());
         Assertions.assertEquals("t", unnest.getAlias().getName());
     }
+
+    @Test
+    void testAggregateFunctionIgnoreNullsBeforeOrderBy() throws JSQLParserException {
+        String sqlStr = "SELECT ARRAY_AGG(x IGNORE NULLS ORDER BY x) FROM t";
+        TestUtils.assertSqlCanBeParsedAndDeparsed(sqlStr, true);
+    }
+
+    @Test
+    void testAggregateFunctionIgnoreNullsOrderByLimit() throws JSQLParserException {
+        String sqlStr = "SELECT ARRAY_AGG(DISTINCT x IGNORE NULLS ORDER BY x DESC LIMIT 5) FROM t";
+        TestUtils.assertSqlCanBeParsedAndDeparsed(sqlStr, true);
+    }
+
+    @Test
+    void testAggregateFunctionOrderByWithoutNullHandling() throws JSQLParserException {
+        String sqlStr = "SELECT ARRAY_AGG(x ORDER BY x) FROM t";
+        TestUtils.assertSqlCanBeParsedAndDeparsed(sqlStr, true);
+    }
 }