EVOLUTION-MANAGER

Edit File: mrr_icp_extra.result

call mtr.add_suppression("Can't find record in .*"); set @mrr_icp_extra_tmp=@@optimizer_switch; set optimizer_switch='mrr=on,mrr_sort_keys=on,index_condition_pushdown=on'; SET NAMES latin1; CREATE TABLE t1 (s1 char(10) COLLATE latin1_german1_ci, s2 char(10) COLLATE latin1_swedish_ci, KEY(s1), KEY(s2)); INSERT INTO t1 VALUES ('a','a'); INSERT INTO t1 VALUES ('b','b'); INSERT INTO t1 VALUES ('c','c'); INSERT INTO t1 VALUES ('d','d'); INSERT INTO t1 VALUES ('e','e'); INSERT INTO t1 VALUES ('f','f'); INSERT INTO t1 VALUES ('g','g'); INSERT INTO t1 VALUES ('h','h'); INSERT INTO t1 VALUES ('i','i'); INSERT INTO t1 VALUES ('j','j'); EXPLAIN SELECT * FROM t1 WHERE s1='a'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref s1 s1 11 const 1 Using index condition EXPLAIN SELECT * FROM t1 WHERE s2='a'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref s2 s2 11 const 1 Using index condition EXPLAIN SELECT * FROM t1 WHERE s1='a' COLLATE latin1_german1_ci; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref s1 s1 11 const 1 Using index condition EXPLAIN SELECT * FROM t1 WHERE s2='a' COLLATE latin1_german1_ci; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL s2 NULL NULL NULL 10 Using where EXPLAIN SELECT * FROM t1 WHERE s1 BETWEEN 'a' AND 'b' COLLATE latin1_german1_ci; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range s1 s1 11 NULL 2 Using index condition; Rowid-ordered scan EXPLAIN SELECT * FROM t1 WHERE s2 BETWEEN 'a' AND 'b' COLLATE latin1_german1_ci; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL s2 NULL NULL NULL 10 Using where EXPLAIN SELECT * FROM t1 WHERE s1 IN ('a','b' COLLATE latin1_german1_ci); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range s1 s1 11 NULL 2 Using index condition; Rowid-ordered scan EXPLAIN SELECT * FROM t1 WHERE s2 IN ('a','b' COLLATE latin1_german1_ci); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL s2 NULL NULL NULL 10 Using where EXPLAIN SELECT * FROM t1 WHERE s1 LIKE 'a' COLLATE latin1_german1_ci; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range s1 s1 11 NULL 1 Using index condition; Rowid-ordered scan EXPLAIN SELECT * FROM t1 WHERE s2 LIKE 'a' COLLATE latin1_german1_ci; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL s2 NULL NULL NULL 10 Using where DROP TABLE t1; # # CREATE TABLE t2 (a varchar(32), b int(11), c float, d double, UNIQUE KEY a (a,b,c), KEY b (b), KEY c (c)); CREATE TABLE t1 (a varchar(32), b char(3), UNIQUE KEY a (a,b), KEY b (b)); CREATE TABLE t3 (a varchar(32), b char(3), UNIQUE KEY a (a,b)); INSERT INTO t3 SELECT * FROM t1; EXPLAIN SELECT d FROM t1, t2 WHERE t2.b=14 AND t2.a=t1.a AND 5.1<t2.c AND t1.b='DE' ORDER BY t2.c LIMIT 1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables SELECT d FROM t1, t2 WHERE t2.b=14 AND t2.a=t1.a AND 5.1<t2.c AND t1.b='DE' ORDER BY t2.c LIMIT 1; d DROP TABLE t1,t2,t3; # # create table t1(a int, b int, index(b)); insert into t1 values (2, 1), (1, 1), (4, NULL), (3, NULL), (6, 2), (5, 2); insert into t1 values (2, 11), (1, 11), (4, 14), (3, 14), (6, 12), (5, 12); explain select * from t1 where b=1 or b is null order by a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref_or_null b b 5 const 4 Using index condition; Using where; Using filesort select * from t1 where b=1 or b is null order by a; a b 1 1 2 1 3 NULL 4 NULL explain select * from t1 where b=2 or b is null order by a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref_or_null b b 5 const 3 Using index condition; Using where; Using filesort select * from t1 where b=2 or b is null order by a; a b 3 NULL 4 NULL 5 2 6 2 drop table t1; # # CREATE TABLE t1 ( FieldKey varchar(36) NOT NULL default '', LongVal bigint(20) default NULL, StringVal mediumtext, KEY FieldKey (FieldKey), KEY LongField (FieldKey,LongVal), KEY StringField (FieldKey,StringVal(32)) ); INSERT INTO t1 VALUES ('0',3,'0'),('0',2,'1'),('0',1,'2'),('1',2,'1'),('1',1,'3'), ('1',0,'2'),('2',3,'0'),('2',2,'1'),('2',1,'2'),('2',3,'0'),('2',2,'1'),('2',1,'2'),('3',2,'1'),('3',1,'2'),('3','3','3'); EXPLAIN SELECT * FROM t1 IGNORE INDEX (LongField, StringField) WHERE FieldKey > '2' ORDER BY LongVal; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range FieldKey FieldKey 38 NULL 4 Using index condition; Rowid-ordered scan; Using filesort EXPLAIN SELECT * FROM t1 IGNORE INDEX (FieldKey, LongField) WHERE FieldKey > '2' ORDER BY LongVal; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range StringField StringField 38 NULL 4 Using where; Using filesort SELECT * FROM t1 WHERE FieldKey > '2' ORDER BY LongVal; FieldKey LongVal StringVal 3 1 2 3 2 1 3 3 3 DROP TABLE t1; # # CREATE TABLE t1 (a int not null, b int, c int, key(b), key(c), key(a,b), key(c,a)); INSERT into t1 values (0, null, 0), (0, null, 1), (0, null, 2), (0, null,3), (1,1,4); create table t2 (a int not null, b int, c int, key(b), key(c), key(a)); INSERT into t2 values (1,1,1), (2,2,2); optimize table t1; Table Op Msg_type Msg_text test.t1 optimize status OK explain select * from t1 force index (a) where a=0 or a=2; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 4 NULL 4 Using index condition; Using where; Rowid-ordered scan select * from t1 force index (a) where a=0 or a=2; a b c 0 NULL 0 0 NULL 1 0 NULL 2 0 NULL 3 drop table t1; # # create table t1 ( pk1 int not null, pk2 int not null, key1 int not null, key2 int not null, pktail1ok int not null, pktail2ok int not null, pktail3bad int not null, pktail4bad int not null, pktail5bad int not null, pk2copy int not null, badkey int not null, filler1 char (200), filler2 char (200), key (key1), key (key2), /* keys with tails from CPK members */ key (pktail1ok, pk1), key (pktail2ok, pk1, pk2), key (pktail3bad, pk2, pk1), key (pktail4bad, pk1, pk2copy), key (pktail5bad, pk1, pk2, pk2copy), primary key (pk1, pk2) ); explain select * from t1 where pk1 = 1 and pk2 < 80 and key1=0; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range PRIMARY,key1 PRIMARY 8 NULL 7 Using index condition; Using where; Rowid-ordered scan select * from t1 where pk1 = 1 and pk2 < 80 and key1=0; pk1 pk2 key1 key2 pktail1ok pktail2ok pktail3bad pktail4bad pktail5bad pk2copy badkey filler1 filler2 1 19 0 0 0 0 0 0 0 19 0 filler-data-19 filler2 1 18 0 0 0 0 0 0 0 18 0 filler-data-18 filler2 1 17 0 0 0 0 0 0 0 17 0 filler-data-17 filler2 1 16 0 0 0 0 0 0 0 16 0 filler-data-16 filler2 1 15 0 0 0 0 0 0 0 15 0 filler-data-15 filler2 1 14 0 0 0 0 0 0 0 14 0 filler-data-14 filler2 1 13 0 0 0 0 0 0 0 13 0 filler-data-13 filler2 1 12 0 0 0 0 0 0 0 12 0 filler-data-12 filler2 1 11 0 0 0 0 0 0 0 11 0 filler-data-11 filler2 1 10 0 0 0 0 0 0 0 10 0 filler-data-10 filler2 drop table t1; # # CREATE TABLE t1 ( f1 int, f4 varchar(32), f5 int, PRIMARY KEY (f1), KEY (f4) ); INSERT INTO t1 VALUES (5,'H',1), (9,'g',0), (527,'i',0), (528,'y',1), (529,'S',6), (530,'m',7), (531,'b',2), (532,'N',1), (533,'V',NULL), (534,'l',1), (535,'M',0), (536,'w',1), (537,'j',5), (538,'l',0), (539,'n',2), (540,'m',2), (541,'r',2), (542,'l',2), (543,'h',3),(544,'o',0), (956,'h',0), (957,'g',0), (958,'W',5), (959,'s',3), (960,'w',0), (961,'q',0), (962,'e',NULL), (963,'u',7), (964,'q',1), (965,'N',NULL), (966,'e',0), (967,'t',3), (968,'e',6), (969,'f',NULL), (970,'j',0), (971,'s',3), (972,'I',0), (973,'h',4), (974,'g',1), (975,'s',0), (976,'r',3), (977,'x',1), (978,'v',8), (979,'j',NULL), (980,'z',7), (981,'t',9), (982,'j',5), (983,'u',NULL), (984,'g',6), (985,'w',1), (986,'h',1), (987,'v',0), (988,'v',0), (989,'c',2), (990,'b',7), (991,'z',0), (992,'M',1), (993,'u',2), (994,'r',2), (995,'b',4), (996,'A',2), (997,'u',0), (998,'a',0), (999,'j',2), (1,'I',2); EXPLAIN SELECT * FROM t1 WHERE (f1 < 535 OR f1 > 985) AND ( f4='r' OR f4 LIKE 'a%' ) ; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range PRIMARY,f4 f4 35 NULL 5 Using index condition; Using where; Rowid-ordered scan SELECT * FROM t1 WHERE (f1 < 535 OR f1 > 985) AND ( f4='r' OR f4 LIKE 'a%' ) ; f1 f4 f5 994 r 2 996 A 2 998 a 0 drop table t1; # # drop table if exists t1,t2,t3; --- Testing varchar --- --- Testing varchar --- create table t1 (v varchar(10), c char(10), t text); insert into t1 values('+ ', '+ ', '+ '); set @a=repeat(' ',20); insert into t1 values (concat('+',@a),concat('+',@a),concat('+',@a)); Warnings: Note 1265 Data truncated for column 'v' at row 1 select concat('*',v,'*',c,'*',t,'*') from t1; concat('*',v,'*',c,'*',t,'*') *+ *+*+ * *+ *+*+ * show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(10) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 create table t2 like t1; show create table t2; Table Create Table t2 CREATE TABLE `t2` ( `v` varchar(10) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 create table t3 select * from t1; show create table t3; Table Create Table t3 CREATE TABLE `t3` ( `v` varchar(10) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 alter table t1 modify c varchar(10); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(10) DEFAULT NULL, `c` varchar(10) DEFAULT NULL, `t` text DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 alter table t1 modify v char(10); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` char(10) DEFAULT NULL, `c` varchar(10) DEFAULT NULL, `t` text DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 alter table t1 modify t varchar(10); Warnings: Note 1265 Data truncated for column 't' at row 2 show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` char(10) DEFAULT NULL, `c` varchar(10) DEFAULT NULL, `t` varchar(10) DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 select concat('*',v,'*',c,'*',t,'*') from t1; concat('*',v,'*',c,'*',t,'*') *+*+*+ * *+*+*+ * drop table t1,t2,t3; create table t1 (v varchar(10), c char(10), t text, key(v), key(c), key(t(10))); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(10) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text DEFAULT NULL, KEY `v` (`v`), KEY `c` (`c`), KEY `t` (`t`(10)) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 select count(*) from t1; count(*) 270 insert into t1 values(concat('a',char(1)),concat('a',char(1)),concat('a',char(1))); select count(*) from t1 where v='a'; count(*) 10 select count(*) from t1 where c='a'; count(*) 10 select count(*) from t1 where t='a'; count(*) 10 select count(*) from t1 where v='a '; count(*) 10 select count(*) from t1 where c='a '; count(*) 10 select count(*) from t1 where t='a '; count(*) 10 select count(*) from t1 where v between 'a' and 'a '; count(*) 10 select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n'; count(*) 10 select count(*) from t1 where v like 'a%'; count(*) 11 select count(*) from t1 where c like 'a%'; count(*) 11 select count(*) from t1 where t like 'a%'; count(*) 11 select count(*) from t1 where v like 'a %'; count(*) 9 explain select count(*) from t1 where v='a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 13 const # Using where; Using index explain select count(*) from t1 where c='a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref c c 11 const # Using where; Using index explain select count(*) from t1 where t='a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref t t 13 const # Using where explain select count(*) from t1 where v like 'a%'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range v v 13 NULL # Using where; Using index explain select count(*) from t1 where v between 'a' and 'a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 13 const # Using where; Using index explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 13 const # Using where; Using index alter table t1 add unique(v); ERROR 23000: Duplicate entry '{ ' for key 'v_2' show warnings; Level Code Message Error 1062 Duplicate entry 'a
' for key 'v_2' alter table t1 add key(v); Warnings: Note 1831 Duplicate index `v_2`. This is deprecated and will be disallowed in a future release select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a'; qq *a*a*a* *a *a*a * *a *a*a * *a *a*a * *a *a*a * *a *a*a * *a *a*a * *a *a*a * *a *a*a * *a *a*a * explain select * from t1 where v='a'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v,v_2 # 13 const # # select v,count(*) from t1 group by v limit 10; v count(*) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select v,count(t) from t1 group by v limit 10; v count(t) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select v,count(c) from t1 group by v limit 10; v count(c) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result v,count(t) from t1 group by v limit 10; v count(t) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result v,count(c) from t1 group by v limit 10; v count(c) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select c,count(*) from t1 group by c limit 10; c count(*) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select c,count(t) from t1 group by c limit 10; c count(t) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result c,count(t) from t1 group by c limit 10; c count(t) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select t,count(*) from t1 group by t limit 10; t count(*) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select t,count(t) from t1 group by t limit 10; t count(t) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result t,count(t) from t1 group by t limit 10; t count(t) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 alter table t1 modify v varchar(300), drop key v, drop key v_2, add key v (v); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(300) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text DEFAULT NULL, KEY `c` (`c`), KEY `t` (`t`(10)), KEY `v` (`v`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 select count(*) from t1 where v='a'; count(*) 10 select count(*) from t1 where v='a '; count(*) 10 select count(*) from t1 where v between 'a' and 'a '; count(*) 10 select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n'; count(*) 10 select count(*) from t1 where v like 'a%'; count(*) 11 select count(*) from t1 where v like 'a %'; count(*) 9 explain select count(*) from t1 where v='a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 303 const # Using where; Using index explain select count(*) from t1 where v like 'a%'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range v v 303 NULL # Using where; Using index explain select count(*) from t1 where v between 'a' and 'a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 303 const # Using where; Using index explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 303 const # Using where; Using index explain select * from t1 where v='a'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 303 const # # select v,count(*) from t1 group by v limit 10; v count(*) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select v,count(t) from t1 group by v limit 10; v count(t) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result v,count(t) from t1 group by v limit 10; v count(t) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 alter table t1 drop key v, add key v (v(30)); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(300) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text DEFAULT NULL, KEY `c` (`c`), KEY `t` (`t`(10)), KEY `v` (`v`(30)) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 select count(*) from t1 where v='a'; count(*) 10 select count(*) from t1 where v='a '; count(*) 10 select count(*) from t1 where v between 'a' and 'a '; count(*) 10 select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n'; count(*) 10 select count(*) from t1 where v like 'a%'; count(*) 11 select count(*) from t1 where v like 'a %'; count(*) 9 explain select count(*) from t1 where v='a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 33 const # Using where explain select count(*) from t1 where v like 'a%'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range v v 33 NULL # Using where explain select count(*) from t1 where v between 'a' and 'a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 33 const # Using where explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 33 const # Using where explain select * from t1 where v='a'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 33 const # # select v,count(*) from t1 group by v limit 10; v count(*) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select v,count(t) from t1 group by v limit 10; v count(t) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result v,count(t) from t1 group by v limit 10; v count(t) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 alter table t1 modify v varchar(600), drop key v, add key v (v); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(600) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text DEFAULT NULL, KEY `c` (`c`), KEY `t` (`t`(10)), KEY `v` (`v`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 select v,count(*) from t1 group by v limit 10; v count(*) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select v,count(t) from t1 group by v limit 10; v count(t) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result v,count(t) from t1 group by v limit 10; v count(t) a
1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 drop table t1; create table t1 (a char(10), unique (a)); insert into t1 values ('a '); insert into t1 values ('a '); ERROR 23000: Duplicate entry 'a' for key 'a' alter table t1 modify a varchar(10); insert into t1 values ('a '),('a '),('a '),('a '); ERROR 23000: Duplicate entry 'a ' for key 'a' insert into t1 values ('a '); ERROR 23000: Duplicate entry 'a ' for key 'a' insert into t1 values ('a '); ERROR 23000: Duplicate entry 'a ' for key 'a' insert into t1 values ('a '); ERROR 23000: Duplicate entry 'a ' for key 'a' update t1 set a='a ' where a like 'a%'; select concat(a,'.') from t1; concat(a,'.') a . update t1 set a='abc ' where a like 'a '; select concat(a,'.') from t1; concat(a,'.') a . update t1 set a='a ' where a like 'a %'; select concat(a,'.') from t1; concat(a,'.') a . update t1 set a='a ' where a like 'a '; select concat(a,'.') from t1; concat(a,'.') a . drop table t1; create table t1 (v varchar(10), c char(10), t text, key(v(5)), key(c(5)), key(t(5))); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(10) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text DEFAULT NULL, KEY `v` (`v`(5)), KEY `c` (`c`(5)), KEY `t` (`t`(5)) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 drop table t1; create table t1 (v char(10) character set utf8); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` char(10) CHARACTER SET utf8 DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 drop table t1; create table t1 (v varchar(10), c char(10)) row_format=fixed; show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(10) DEFAULT NULL, `c` char(10) DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 ROW_FORMAT=FIXED insert into t1 values('a','a'),('a ','a '); select concat('*',v,'*',c,'*') from t1; concat('*',v,'*',c,'*') *a*a* *a *a* drop table t1; create table t1 (v varchar(65530), key(v(10))); insert into t1 values(repeat('a',65530)); select length(v) from t1 where v=repeat('a',65530); length(v) 65530 drop table t1; create table t1(a int, b varchar(12), key ba(b, a)); insert into t1 values (1, 'A'), (20, NULL); explain select * from t1 where a=20 and b is null; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref ba ba 20 const,const 1 Using where; Using index select * from t1 where a=20 and b is null; a b 20 NULL drop table t1; # # drop database if exists world; CREATE DATABASE world; use world; CREATE TABLE Country ( Code char(3) NOT NULL default '', Name char(52) NOT NULL default '', SurfaceArea float(10,2) NOT NULL default '0.00', Population int(11) NOT NULL default '0', Capital int(11) default NULL, PRIMARY KEY (Code), UNIQUE INDEX (Name) ); CREATE TABLE City ( ID int(11) NOT NULL auto_increment, Name char(35) NOT NULL default '', Country char(3) NOT NULL default '', Population int(11) NOT NULL default '0', PRIMARY KEY (ID), INDEX (Population), INDEX (Country) ); CREATE TABLE CountryLanguage ( Country char(3) NOT NULL default '', Language char(30) NOT NULL default '', Percentage float(3,1) NOT NULL default '0.0', PRIMARY KEY (Country, Language), INDEX (Percentage) ); SELECT * FROM City WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'F')) AND (Population > 101000 AND Population < 102000); ID Name Country Population 637 Mit Ghamr EGY 101801 707 Marbella ESP 101144 3792 Tartu EST 101246 4032 Cambridge USA 101355 explain SELECT * FROM City WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'F')) AND (Population > 101000 AND Population < 102000); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE City range Population,Country Population 4 NULL # Using index condition; Using where; Rowid-ordered scan explain SELECT * FROM City WHERE (Name < 'Ac' AND (Country > 'A' AND Country < 'B')) OR (Name BETWEEN 'P' AND 'Pb' AND (Population > 101000 AND Population < 110000)); id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE City index_merge Population,Country Country,Population 3,4 NULL # Using sort_union(Country,Population); Using where SELECT * FROM City WHERE (Name < 'Ac' AND (Country > 'A' AND Country < 'B')) OR (Name BETWEEN 'P' AND 'Pb' AND (Population > 101000 AND Population < 110000)); ID Name Country Population 65 Abu Dhabi ARE 398695 168 Pabna BGD 103277 189 Parakou BEN 103577 750 Paarl ZAF 105768 2865 Pak Pattan PAK 107800 SELECT * FROM City WHERE Name LIKE 'M%' AND Population > 7000000; ID Name Country Population 1024 Mumbai (Bombay) IND 10500000 3580 Moscow RUS 8389200 explain SELECT * FROM City WHERE Name LIKE 'M%' AND Population > 7000000; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE City range Population Population 4 NULL # Using index condition; Using where; Rowid-ordered scan explain SELECT * FROM City WHERE Name BETWEEN 'G' AND 'K' AND Population > 500000 AND Country LIKE 'C%'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE City range Population,Country # # NULL # Using index condition; Using where; Rowid-ordered scan SELECT * FROM City WHERE Name BETWEEN 'G' AND 'K' AND Population > 500000 AND Country LIKE 'C%'; ID Name Country Population 1895 Harbin CHN 4289800 1904 Jinan CHN 2278100 1905 Hangzhou CHN 2190500 1914 Guiyang CHN 1465200 1916 Hefei CHN 1369100 1923 Jilin CHN 1040000 1927 Hohhot CHN 916700 1928 Handan CHN 840000 1937 Huainan CHN 700000 1938 Jixi CHN 683885 1944 Jinzhou CHN 570000 1950 Hegang CHN 520000 explain SELECT * FROM City WHERE Name BETWEEN 'G' AND 'J' AND Population > 500000 AND Country LIKE 'C%'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE City range Population,Country # # NULL # Using index condition; Using where; Rowid-ordered scan SELECT * FROM City WHERE Name BETWEEN 'G' AND 'J' AND Population > 500000 AND Country LIKE 'C%'; ID Name Country Population 1895 Harbin CHN 4289800 1905 Hangzhou CHN 2190500 1914 Guiyang CHN 1465200 1916 Hefei CHN 1369100 1927 Hohhot CHN 916700 1928 Handan CHN 840000 1937 Huainan CHN 700000 1950 Hegang CHN 520000 drop database world; use test; set @mrr_icp_extra_tmp=@@optimizer_switch;