database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2026-01-06 05:22:24 +03:00
Code Activity

EXPLAIN UNION using same routing which used for execution which allow return correct bug messages (Bug #3639)

Browse Source 
EXPLAIN of hidden SELECT of UNION
This commit is contained in:
bell@sanja.is.com.ua
2004-05-06 20:40:21 +03:00
parent ec33d794d8
commit 3aae50e8c0
11 changed files with 179 additions and 74 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
mysql-test/r/derived.result
View File

@@ -94,11 +94,13 @@ id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 3
2 DERIVED t1 ALL NULL NULL NULL NULL 4
3 UNION t1 ALL NULL NULL NULL NULL 4
-2 UNION RESULT <union2> ALL NULL NULL NULL NULL NULL
explain select * from (select * from t1 union all select * from t1) a;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 8
2 DERIVED t1 ALL NULL NULL NULL NULL 4
3 UNION t1 ALL NULL NULL NULL NULL 4
-2 UNION RESULT <union2> ALL NULL NULL NULL NULL NULL
CREATE TABLE t2 (a int not null);
insert into t2 values(1);
select * from (select * from t1 where t1.a=(select a from t2 where t2.a=t1.a)) a;
@@ -246,8 +248,10 @@ id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived4> ALL NULL NULL NULL NULL 2
4 DERIVED t1 ALL NULL NULL NULL NULL 2
5 UNION t1 ALL NULL NULL NULL NULL 2
-4 UNION RESULT <union4> ALL NULL NULL NULL NULL NULL
2 DERIVED t1 ALL NULL NULL NULL NULL 2
3 UNION t1 ALL NULL NULL NULL NULL 2
-2 UNION RESULT <union2> ALL NULL NULL NULL NULL NULL
drop table t1;
CREATE TABLE `t1` (
`N` int(11) unsigned NOT NULL default '0',