From fbebb47efebb53cc0638ad7b84b3512545a04af9 Mon Sep 17 00:00:00 2001 From: "igor@olga.mysql.com" <> Date: Sat, 26 May 2007 10:33:01 -0700 Subject: [PATCH] Fixed bug #28571. Outer join queries with ON conditions over constant outer tables did not return null complemented rows when conditions were evaluated to FALSE. Wrong results were returned because the conditions over constant outer tables, when being pushed down, were erroneously enclosed into the guard function used for WHERE conditions. --- mysql-test/r/join_outer.result | 15 ++++++++++ mysql-test/t/join_outer.test | 16 ++++++++++ sql/sql_select.cc | 54 ++++++++++++++++++---------------- 3 files changed, 60 insertions(+), 25 deletions(-) diff --git a/mysql-test/r/join_outer.result b/mysql-test/r/join_outer.result index c62601946c2..1366a8fe97a 100644 --- a/mysql-test/r/join_outer.result +++ b/mysql-test/r/join_outer.result @@ -1239,3 +1239,18 @@ Handler_read_prev 0 Handler_read_rnd 0 Handler_read_rnd_next 6 DROP TABLE t1,t2; +CREATE TABLE t1 (c int PRIMARY KEY, e int NOT NULL); +INSERT INTO t1 VALUES (1,0), (2,1); +CREATE TABLE t2 (d int PRIMARY KEY); +INSERT INTO t2 VALUES (1), (2), (3); +EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1 +1 SIMPLE t2 index NULL PRIMARY 4 NULL 3 Using where; Using index; Not exists +SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL; +c e d +1 0 NULL +SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d<=>NULL; +c e d +1 0 NULL +DROP TABLE t1,t2; diff --git a/mysql-test/t/join_outer.test b/mysql-test/t/join_outer.test index 51e79a20d65..1a59dbf8fc2 100644 --- a/mysql-test/t/join_outer.test +++ b/mysql-test/t/join_outer.test @@ -845,3 +845,19 @@ SELECT t1.id, a FROM t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t2.b IS NULL; show status like 'Handler_read%'; DROP TABLE t1,t2; + +# +# Bug 28571: outer join with false on condition over constant tables +# + +CREATE TABLE t1 (c int PRIMARY KEY, e int NOT NULL); +INSERT INTO t1 VALUES (1,0), (2,1); +CREATE TABLE t2 (d int PRIMARY KEY); +INSERT INTO t2 VALUES (1), (2), (3); + +EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL; +SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL; +SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d<=>NULL; + +DROP TABLE t1,t2; + diff --git a/sql/sql_select.cc b/sql/sql_select.cc index db6c134b203..ecdb727bcb4 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -5666,28 +5666,6 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond) join->const_table_map, (table_map) 0); DBUG_EXECUTE("where",print_where(const_cond,"constants");); - for (JOIN_TAB *tab= join->join_tab+join->const_tables; - tab < join->join_tab+join->tables ; tab++) - { - if (*tab->on_expr_ref) - { - JOIN_TAB *cond_tab= tab->first_inner; - COND *tmp= make_cond_for_table(*tab->on_expr_ref, - join->const_table_map, - ( table_map) 0); - if (!tmp) - continue; - tmp= new Item_func_trig_cond(tmp, &cond_tab->not_null_compl); - if (!tmp) - DBUG_RETURN(1); - tmp->quick_fix_field(); - cond_tab->select_cond= !cond_tab->select_cond ? tmp : - new Item_cond_and(cond_tab->select_cond,tmp); - if (!cond_tab->select_cond) - DBUG_RETURN(1); - cond_tab->select_cond->quick_fix_field(); - } - } if (const_cond && !const_cond->val_int()) { DBUG_PRINT("info",("Found impossible WHERE condition")); @@ -5918,13 +5896,39 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond) } /* - Push down all predicates from on expressions. - Each of these predicated are guarded by a variable + Push down conditions from all on expressions. + Each of these conditions are guarded by a variable that turns if off just before null complemented row for - outer joins is formed. Thus, the predicates from an + outer joins is formed. Thus, the condition from an 'on expression' are guaranteed not to be checked for the null complemented row. */ + + /* First push down constant conditions from on expressions */ + for (JOIN_TAB *tab= join->join_tab+join->const_tables; + tab < join->join_tab+join->tables ; tab++) + { + if (*tab->on_expr_ref) + { + JOIN_TAB *cond_tab= tab->first_inner; + COND *tmp= make_cond_for_table(*tab->on_expr_ref, + join->const_table_map, + (table_map) 0); + if (!tmp) + continue; + tmp= new Item_func_trig_cond(tmp, &cond_tab->not_null_compl); + if (!tmp) + DBUG_RETURN(1); + tmp->quick_fix_field(); + cond_tab->select_cond= !cond_tab->select_cond ? tmp : + new Item_cond_and(cond_tab->select_cond,tmp); + if (!cond_tab->select_cond) + DBUG_RETURN(1); + cond_tab->select_cond->quick_fix_field(); + } + } + + /* Push down non-constant conditions from on expressions */ JOIN_TAB *last_tab= tab; while (first_inner_tab && first_inner_tab->last_inner == last_tab) {