explain extended select * from t2 where t2.a in (select a from t1);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t2 index a a 5 NULL 4 100.00 Using where; Using index
1 PRIMARY t1 ref a a 5 test.t2.a 100 100.00 Using index; FirstMatch(t2)
1 PRIMARY t1 ref a a 5 test.t2.a 101 100.00 Using index; FirstMatch(t2)
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where (`test`.`t1`.`a` = `test`.`t2`.`a`)
select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
...
...
@@ -1352,7 +1352,7 @@ a
explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t2 index a a 5 NULL 4 100.00 Using where; Using index
1 PRIMARY t1 ref a a 5 test.t2.a 100 100.00 Using where; Using index; FirstMatch(t2)
1 PRIMARY t1 ref a a 5 test.t2.a 101 100.00 Using where; Using index; FirstMatch(t2)
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` <> 30))
select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
...
...
@@ -1363,7 +1363,7 @@ explain extended select * from t2 where t2.a in (select t1.a from t1,t3 where t1
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t2 index a a 5 NULL 4 100.00 Using where; Using index
1 PRIMARY t3 index a a 5 NULL 3 100.00 Using where; Using index
1 PRIMARY t1 ref a a 10 test.t2.a,test.t3.a 11 100.00 Using index; FirstMatch(t2)
1 PRIMARY t1 ref a a 10 test.t2.a,test.t3.a 116 100.00 Using index; FirstMatch(t2)
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1` join `test`.`t3`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` = `test`.`t3`.`a`))
insert into t1 values (3,31);
...
...
@@ -1379,7 +1379,7 @@ a
explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t2 index a a 5 NULL 4 100.00 Using where; Using index
1 PRIMARY t1 ref a a 5 test.t2.a 100 100.00 Using where; Using index; FirstMatch(t2)
1 PRIMARY t1 ref a a 5 test.t2.a 101 100.00 Using where; Using index; FirstMatch(t2)
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` <> 30))
@@ -123,14 +123,14 @@ DOCID DOCNAME DOCTYPEID FOLDERID AUTHOR CREATED TITLE SUBTITLE DOCABSTRACT PUBLI
c373e9f5ad07993f3859444553544200 Last Discussion c373e9f5ad079174ff17444553544200 c373e9f5ad0796c0eca4444553544200 Goldilocks 2003-06-09 11:21:06 Title: Last Discussion NULL Setting new abstract and keeping doc checked out 2003-06-09 10:51:26 2003-06-09 10:51:26 NULL NULL NULL 03eea05112b845949f3fd03278b5fe43 2003-06-09 11:21:06 admin 0 NULL Discussion NULL NULL
EXPLAIN SELECT t2.*, t4.DOCTYPENAME, t1.CONTENTSIZE,t1.MIMETYPE FROM t2 INNER JOIN t4 ON t2.DOCTYPEID = t4.DOCTYPEID LEFT OUTER JOIN t1 ON t2.DOCID = t1.DOCID WHERE t2.FOLDERID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID='2f6161e879db43c1a5b82c21ddc49089' AND t3.FOLDERNAME = 'Level1') AND t3.FOLDERNAME = 'Level2') AND t3.FOLDERNAME = 'Level3') AND t3.FOLDERNAME = 'CopiedFolder') AND t3.FOLDERNAME = 'Movie Reviews') AND t2.DOCNAME = 'Last Discussion';
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL DDOCTYPEID_IDX NULL NULL NULL 9 Using where
1 PRIMARY t3 ref PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX CMFLDRPARNT_IDX 35 const 6 Using index condition; Using where
1 PRIMARY t3 ref PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX CMFLDRPARNT_IDX 35 test.t3.FOLDERID 1 Using where
1 PRIMARY t3 ref PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX CMFLDRPARNT_IDX 35 test.t3.FOLDERID 1 Using where
1 PRIMARY t3 ref PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX CMFLDRPARNT_IDX 35 test.t3.FOLDERID 1 Using where
1 PRIMARY t3 ref PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX CMFLDRPARNT_IDX 35 test.t3.FOLDERID 1 Using where
1 PRIMARY t2 ALL DDOCTYPEID_IDX,DFOLDERID_IDX NULL NULL NULL 9 Using where; Using join buffer (flat, BNL join)
explain extended select * from t2 where t2.a in (select a from t1);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t2 index a a 5 NULL 4 100.00 Using where; Using index
1 PRIMARY t1 ref a a 5 test.t2.a 100 100.00 Using index; FirstMatch(t2)
1 PRIMARY t1 ref a a 5 test.t2.a 101 100.00 Using index; FirstMatch(t2)
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where (`test`.`t1`.`a` = `test`.`t2`.`a`)
select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
...
...
@@ -1356,7 +1356,7 @@ a
explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t2 index a a 5 NULL 4 100.00 Using where; Using index
1 PRIMARY t1 ref a a 5 test.t2.a 100 100.00 Using where; Using index; FirstMatch(t2)
1 PRIMARY t1 ref a a 5 test.t2.a 101 100.00 Using where; Using index; FirstMatch(t2)
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` <> 30))
select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
...
...
@@ -1367,7 +1367,7 @@ explain extended select * from t2 where t2.a in (select t1.a from t1,t3 where t1
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t2 index a a 5 NULL 4 100.00 Using where; Using index
1 PRIMARY t3 index a a 5 NULL 3 100.00 Using where; Using index
1 PRIMARY t1 ref a a 10 test.t2.a,test.t3.a 11 100.00 Using index; FirstMatch(t2)
1 PRIMARY t1 ref a a 10 test.t2.a,test.t3.a 116 100.00 Using index; FirstMatch(t2)
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1` join `test`.`t3`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` = `test`.`t3`.`a`))
insert into t1 values (3,31);
...
...
@@ -1383,7 +1383,7 @@ a
explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t2 index a a 5 NULL 4 100.00 Using where; Using index
1 PRIMARY t1 ref a a 5 test.t2.a 100 100.00 Using where; Using index; FirstMatch(t2)
1 PRIMARY t1 ref a a 5 test.t2.a 101 100.00 Using where; Using index; FirstMatch(t2)
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` <> 30))
2 SUBQUERY t2_16 ALL NULL NULL NULL NULL 3 100.00 Using where
Warnings:
Note 1003 select left(`test`.`t1_16`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_16`.`a2`,7) AS `left(a2,7)` from `test`.`t1_16` semi join (`test`.`t2_16`) where ((`test`.`t2_16`.`b1` > '0') and (`test`.`t1_16`.`a1` = substr(`test`.`t2_16`.`b1`,1,16)))
...
...
@@ -751,7 +751,7 @@ from t1_512
where a1 in (select substring(b1,1,512) from t2_512 where b1 > '0');
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1_512 ALL NULL NULL NULL NULL 3 100.00
1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 517 func 1 100.00 Using where
2 SUBQUERY t2_512 ALL NULL NULL NULL NULL 3 100.00 Using where
Warnings:
Note 1003 select left(`test`.`t1_512`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_512`.`a2`,7) AS `left(a2,7)` from `test`.`t1_512` semi join (`test`.`t2_512`) where ((`test`.`t2_512`.`b1` > '0') and (`test`.`t1_512`.`a1` = substr(`test`.`t2_512`.`b1`,1,512)))
...
...
@@ -847,7 +847,7 @@ from t1_1024
where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0');
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 100.00
1 PRIMARY <subquery2> eq_ref NULL distinct_key 15 func,func 1 100.00 Using where
2 SUBQUERY t2_1024 ALL NULL NULL NULL NULL 3 100.00 Using where
Warnings:
Note 1003 select left(`test`.`t1_1024`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_1024`.`a2`,7) AS `left(a2,7)` from `test`.`t1_1024` semi join (`test`.`t2_1024`) where ((`test`.`t2_1024`.`b1` > '0') and (`test`.`t1_1024`.`a1` = substr(`test`.`t2_1024`.`b1`,1,1024)))
...
...
@@ -941,7 +941,7 @@ from t1_1025
where a1 in (select substring(b1,1,1025) from t2_1025 where b1 > '0');
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1_1025 ALL NULL NULL NULL NULL 3 100.00
1 PRIMARY <subquery2> eq_ref NULL distinct_key 15 func,func 1 100.00 Using where
2 SUBQUERY t2_1025 ALL NULL NULL NULL NULL 3 100.00 Using where
Warnings:
Note 1003 select left(`test`.`t1_1025`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_1025`.`a2`,7) AS `left(a2,7)` from `test`.`t1_1025` semi join (`test`.`t2_1025`) where ((`test`.`t2_1025`.`b1` > '0') and (`test`.`t1_1025`.`a1` = substr(`test`.`t2_1025`.`b1`,1,1025)))
...
...
@@ -1219,7 +1219,7 @@ insert into t1 values ('aa', 'aaaa');
explain select a,b from t1 where b in (select a from t1);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2
1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 3 func 1 Using where