From 2dd4e50d5f74451a5f6bf56d1a36bafffcca878c Mon Sep 17 00:00:00 2001 From: Varun Gupta Date: Wed, 21 Mar 2018 01:34:45 +0530 Subject: MDEV-15555: select from DUAL where false yielding wrong result when in a IN For the query having an IN subquery with no tables, we were converting the subquery with an expression between the left part and the select list of the subquery . This can give incorrect results when we have a condition in the subquery with a dual table (as this is treated as a no table). The fix is that we don't do this conversion when we have conds in the subquery with a dual table. --- sql/item_subselect.cc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'sql/item_subselect.cc') diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc index 46d41fd61e3..57dcbd4f540 100644 --- a/sql/item_subselect.cc +++ b/sql/item_subselect.cc @@ -1746,7 +1746,7 @@ Item_in_subselect::single_value_transformer(JOIN *join) Item* join_having= join->having ? join->having : join->tmp_having; if (!(join_having || select_lex->with_sum_func || select_lex->group_list.elements) && - select_lex->table_list.elements == 0 && + select_lex->table_list.elements == 0 && !join->conds && !select_lex->master_unit()->is_union()) { Item *where_item= (Item*) select_lex->item_list.head(); -- cgit v1.2.1