diff --git a/parser/parser.mly b/parser/parser.mly
index 670a433..c6725d6 100644
--- a/parser/parser.mly
+++ b/parser/parser.mly
@@ -215,6 +215,7 @@ column_reference:
 
 set_function_specification:
   | aggregate_function { $1 }
+(*  | grouping_function { $1 } *)
 
 (*********************************)
 
diff --git a/test/test_ast.ml b/test/test_ast.ml
index 2d17404..840fb14 100644
--- a/test/test_ast.ml
+++ b/test/test_ast.ml
@@ -411,6 +411,10 @@ let test_aggregates () =
   let ast1 =
     Select(
       [
+        Column(
+          Ref("function"),
+          None
+        )
       ],
       TableExpression(
         Some(