diff options
Diffstat (limited to 'sql/item_strfunc.cc')
| -rw-r--r-- | sql/item_strfunc.cc | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc index 4e72f117869..c443364ce52 100644 --- a/sql/item_strfunc.cc +++ b/sql/item_strfunc.cc @@ -294,6 +294,12 @@ String *Item_func_concat::val_str(String *str) { if (!(res=args[i]->val_str(str))) goto null; + /* + CONCAT accumulates its result in the result of its the first + non-empty argument. Because of this we need is_const to be + evaluated only for it. + */ + is_const= args[i]->const_item() || !args[i]->used_tables(); } else { |