ddl: forbid create Generated column with Grouping function (#49930)

close #49909

pkg/ddl/generated_column.go

@@ -289,6 +289,11 @@ type illegalFunctionChecker struct {
 func (c *illegalFunctionChecker) Enter(inNode ast.Node) (outNode ast.Node, skipChildren bool) {
 	switch node := inNode.(type) {
 	case *ast.FuncCallExpr:
+		// Grouping function is not allowed, issue #49909.
+		if node.FnName.L == ast.Grouping {
+			c.hasAggFunc = true
+			return inNode, true
+		}
 		// Blocked functions & non-builtin functions is not allowed
 		_, isFunctionBlocked := expression.IllegalFunctions4GeneratedColumns[node.FnName.L]
 		if isFunctionBlocked || !expression.IsFunctionSupported(node.FnName.L) {

tests/integrationtest/r/ddl/db_integration.result

@@ -1291,3 +1291,10 @@ create temporary table t2(id int primary key, v int);
 select * from t2 where id=234;
 id	v
 commit;
+drop table if exists t;
+create table t(a int, b int as ((grouping(a))) stored);
+Error 1111 (HY000): Invalid use of group function
+create table t(a int);
+alter table t add column  b int as ((grouping(a))) stored;
+Error 1111 (HY000): Invalid use of group function
+drop table t;

tests/integrationtest/t/ddl/db_integration.test

@@ -1108,3 +1108,12 @@ create temporary table t2(id int primary key, v int);
 select * from t2 where id=234;
 commit;
 disconnect conn1;
+
+# Test Generated column use Grouping function, issue #49909.
+drop table if exists t;
+--error 1111
+create table t(a int, b int as ((grouping(a))) stored);
+create table t(a int);
+--error 1111
+alter table t add column  b int as ((grouping(a))) stored;
+drop table t;