diff options
Diffstat (limited to 'sql/sql_select.cc')
| -rw-r--r-- | sql/sql_select.cc | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index d7eed19d619..5cf6c9b1dbe 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -7658,7 +7658,7 @@ static COND *build_equal_items_for_cond(THD *thd, COND *cond, if (and_level) { /* - Retrieve all conjucts of this level detecting the equality + Retrieve all conjuncts of this level detecting the equality that are subject to substitution by multiple equality items and removing each such predicate from the conjunction after having found/created a multiple equality whose inference the predicate is. @@ -7674,6 +7674,15 @@ static COND *build_equal_items_for_cond(THD *thd, COND *cond, li.remove(); } + /* + Check if we eliminated all the predicates of the level, e.g. + (a=a AND b=b AND a=a). + */ + if (!args->elements && + !cond_equal.current_level.elements && + !eq_list.elements) + return new Item_int((longlong) 1, 1); + List_iterator_fast<Item_equal> it(cond_equal.current_level); while ((item_equal= it++)) { @@ -9820,6 +9829,7 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields, table->in_use= thd; table->quick_keys.init(); table->covering_keys.init(); + table->merge_keys.init(); table->keys_in_use_for_query.init(); table->s= share; |