diff options
Diffstat (limited to 'sql/item_cmpfunc.cc')
| -rw-r--r-- | sql/item_cmpfunc.cc | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc index a53bb2e53b6..a65cbbf37d9 100644 --- a/sql/item_cmpfunc.cc +++ b/sql/item_cmpfunc.cc @@ -318,7 +318,18 @@ static bool convert_const_to_int(THD *thd, Item_field *field_item, field_item->field_type() != MYSQL_TYPE_YEAR) return 1; - if ((*item)->can_eval_in_optimize()) + /* + Replace (*item) with its value if the item can be computed. + + Do not replace items that contain aggregate functions: + There can be such items that are constants, e.g. COLLATION(AVG(123)), + but this function is called at Name Resolution phase. + Removing aggregate functions may confuse query plan generation code, e.g. + the optimizer might conclude that the query doesn't need to do grouping + at all. + */ + if ((*item)->can_eval_in_optimize() && + !(*item)->with_sum_func()) { TABLE *table= field->table; MY_BITMAP *old_maps[2] = { NULL, NULL }; @@ -780,7 +791,9 @@ int Arg_comparator::compare_e_string() { String *res1,*res2; res1= (*a)->val_str(&value1); + DBUG_ASSERT((res1 == NULL) == (*a)->null_value); res2= (*b)->val_str(&value2); + DBUG_ASSERT((res2 == NULL) == (*b)->null_value); if (!res1 || !res2) return MY_TEST(res1 == res2); return MY_TEST(sortcmp(res1, res2, compare_collation()) == 0); |