diff --git a/sql/field.cc b/sql/field.cc
index 43244a2f8a6..9d191fb61dc 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -4721,7 +4721,7 @@ String *Field_enum::val_str(String *val_buffer __attribute__((unused)),
 {
   uint tmp=(uint) Field_enum::val_int();
   if (!tmp || tmp > typelib->count)
-    val_ptr->set((char*)"",0);
+    val_ptr->set((const char*)"",0);
   else
     val_ptr->set((const char*) typelib->type_names[tmp-1],
 		 (uint) strlen(typelib->type_names[tmp-1]));