1 files changed, 5 insertions, 1 deletions
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 6834820c0b5..577a98df0d2 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -5119,7 +5119,11 @@ longlong Item_func_isnull::val_int()
 
 void Item_func_isnull::print(String *str, enum_query_type query_type)
 {
-  args[0]->print_parenthesised(str, query_type, precedence());
+  if (const_item() && !args[0]->maybe_null &&
+      !(query_type & (QT_NO_DATA_EXPANSION | QT_VIEW_INTERNAL)))
+    str->append("/*always not null*/ 1");
+  else
+    args[0]->print_parenthesised(str, query_type, precedence());
   str->append(STRING_WITH_LEN(" is null"));
 }