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drop table if exists t1, t2, t3;
set @read_rnd_buffer_size_save= @@read_rnd_buffer_size;
set read_rnd_buffer_size=79;
select @@read_rnd_buffer_size;
@@read_rnd_buffer_size
79
create table t1(a int);
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` int(11) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t2(a int);
insert into t2 select A.a + 10*(B.a + 10*C.a) from t1 A, t1 B, t1 C;
create table t3 (
a char(8) not null, b char(8) not null, filler char(200),
key(a)
);
insert into t3 select @a:=concat('c-', 1000+ A.a, '=w'), @a, 'filler' from t2 A;
insert into t3 select concat('c-', 1000+A.a, '=w'), concat('c-', 2000+A.a, '=w'),
'filler-1' from t2 A;
insert into t3 select concat('c-', 1000+A.a, '=w'), concat('c-', 3000+A.a, '=w'),
'filler-2' from t2 A;
select a,filler from t3 where a >= 'c-9011=w';
a filler
select a,filler from t3 where a >= 'c-1011=w' and a <= 'c-1015=w';
a filler
c-1011=w filler
c-1012=w filler
c-1013=w filler
c-1011=w filler-1
c-1012=w filler-1
c-1013=w filler-1
c-1011=w filler-2
c-1012=w filler-2
c-1013=w filler-2
c-1014=w filler
c-1015=w filler
c-1014=w filler-1
c-1015=w filler-1
c-1014=w filler-2
c-1015=w filler-2
select a,filler from t3 where (a>='c-1011=w' and a <= 'c-1013=w') or
(a>='c-1014=w' and a <= 'c-1015=w');
a filler
c-1011=w filler
c-1012=w filler
c-1013=w filler
c-1011=w filler-1
c-1012=w filler-1
c-1013=w filler-1
c-1011=w filler-2
c-1012=w filler-2
c-1013=w filler-2
c-1014=w filler
c-1015=w filler
c-1014=w filler-1
c-1015=w filler-1
c-1014=w filler-2
c-1015=w filler-2
insert into t3 values ('c-1013=z', 'c-1013=z', 'err');
insert into t3 values ('a-1014=w', 'a-1014=w', 'err');
select a,filler from t3 where (a>='c-1011=w' and a <= 'c-1013=w') or
(a>='c-1014=w' and a <= 'c-1015=w');
a filler
c-1011=w filler
c-1012=w filler
c-1013=w filler
c-1011=w filler-1
c-1012=w filler-1
c-1013=w filler-1
c-1011=w filler-2
c-1012=w filler-2
c-1013=w filler-2
c-1014=w filler
c-1015=w filler
c-1014=w filler-1
c-1015=w filler-1
c-1014=w filler-2
c-1015=w filler-2
delete from t3 where b in ('c-1013=z', 'a-1014=w');
select a,filler from t3 where a='c-1011=w' or a='c-1012=w' or a='c-1013=w' or
a='c-1014=w' or a='c-1015=w';
a filler
c-1011=w filler
c-1012=w filler
c-1013=w filler
c-1011=w filler-1
c-1012=w filler-1
c-1013=w filler-1
c-1011=w filler-2
c-1012=w filler-2
c-1013=w filler-2
c-1014=w filler
c-1015=w filler
c-1014=w filler-1
c-1015=w filler-1
c-1014=w filler-2
c-1015=w filler-2
insert into t3 values ('c-1013=w', 'del-me', 'inserted');
select a,filler from t3 where a='c-1011=w' or a='c-1012=w' or a='c-1013=w' or
a='c-1014=w' or a='c-1015=w';
a filler
c-1011=w filler
c-1012=w filler
c-1013=w filler
c-1011=w filler-1
c-1012=w filler-1
c-1013=w filler-1
c-1011=w filler-2
c-1012=w filler-2
c-1013=w filler-2
c-1014=w filler
c-1015=w filler
c-1014=w filler-1
c-1015=w filler-1
c-1014=w filler-2
c-1015=w filler-2
c-1013=w inserted
delete from t3 where b='del-me';
alter table t3 add primary key(b);
select b,filler from t3 where (b>='c-1011=w' and b<= 'c-1018=w') or
b IN ('c-1019=w', 'c-1020=w', 'c-1021=w',
'c-1022=w', 'c-1023=w', 'c-1024=w');
b filler
c-1011=w filler
c-1012=w filler
c-1013=w filler
c-1014=w filler
c-1015=w filler
c-1016=w filler
c-1017=w filler
c-1018=w filler
c-1019=w filler
c-1020=w filler
c-1021=w filler
c-1022=w filler
c-1023=w filler
c-1024=w filler
select b,filler from t3 where (b>='c-1011=w' and b<= 'c-1020=w') or
b IN ('c-1021=w', 'c-1022=w', 'c-1023=w');
b filler
c-1011=w filler
c-1012=w filler
c-1013=w filler
c-1014=w filler
c-1015=w filler
c-1016=w filler
c-1017=w filler
c-1018=w filler
c-1019=w filler
c-1020=w filler
c-1021=w filler
c-1022=w filler
c-1023=w filler
select b,filler from t3 where (b>='c-1011=w' and b<= 'c-1018=w') or
b IN ('c-1019=w', 'c-1020=w') or
(b>='c-1021=w' and b<= 'c-1023=w');
b filler
c-1011=w filler
c-1012=w filler
c-1013=w filler
c-1014=w filler
c-1015=w filler
c-1016=w filler
c-1017=w filler
c-1018=w filler
c-1019=w filler
c-1020=w filler
c-1021=w filler
c-1022=w filler
c-1023=w filler
create table t4 (a varchar(10), b int, c char(10), filler char(200),
key idx1 (a, b, c));
insert into t4 (filler) select concat('NULL-', 15-a) from t2 order by a limit 15;
insert into t4 (a,b,c,filler)
select 'b-1',NULL,'c-1', concat('NULL-', 15-a) from t2 order by a limit 15;
insert into t4 (a,b,c,filler)
select 'b-1',NULL,'c-222', concat('NULL-', 15-a) from t2 order by a limit 15;
insert into t4 (a,b,c,filler)
select 'bb-1',NULL,'cc-2', concat('NULL-', 15-a) from t2 order by a limit 15;
insert into t4 (a,b,c,filler)
select 'zz-1',NULL,'cc-2', 'filler-data' from t2 order by a limit 500;
explain
select * from t4 where a IS NULL and b IS NULL and (c IS NULL or c='no-such-row1'
or c='no-such-row2');
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t4 range idx1 idx1 29 NULL 10 Using index condition; Using MRR
select * from t4 where a IS NULL and b IS NULL and (c IS NULL or c='no-such-row1'
or c='no-such-row2');
a b c filler
NULL NULL NULL NULL-15
NULL NULL NULL NULL-14
NULL NULL NULL NULL-13
NULL NULL NULL NULL-12
NULL NULL NULL NULL-11
NULL NULL NULL NULL-10
NULL NULL NULL NULL-9
NULL NULL NULL NULL-8
NULL NULL NULL NULL-7
NULL NULL NULL NULL-6
NULL NULL NULL NULL-5
NULL NULL NULL NULL-4
NULL NULL NULL NULL-3
NULL NULL NULL NULL-2
NULL NULL NULL NULL-1
explain
select * from t4 where (a ='b-1' or a='bb-1') and b IS NULL and (c='c-1' or c='cc-2');
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t4 range idx1 idx1 29 NULL 21 Using index condition; Using MRR
select * from t4 where (a ='b-1' or a='bb-1') and b IS NULL and (c='c-1' or c='cc-2');
a b c filler
b-1 NULL c-1 NULL-15
b-1 NULL c-1 NULL-14
b-1 NULL c-1 NULL-13
b-1 NULL c-1 NULL-12
b-1 NULL c-1 NULL-11
b-1 NULL c-1 NULL-10
b-1 NULL c-1 NULL-9
b-1 NULL c-1 NULL-8
b-1 NULL c-1 NULL-7
b-1 NULL c-1 NULL-6
b-1 NULL c-1 NULL-5
b-1 NULL c-1 NULL-4
b-1 NULL c-1 NULL-3
b-1 NULL c-1 NULL-2
b-1 NULL c-1 NULL-1
bb-1 NULL cc-2 NULL-15
bb-1 NULL cc-2 NULL-14
bb-1 NULL cc-2 NULL-13
bb-1 NULL cc-2 NULL-12
bb-1 NULL cc-2 NULL-11
bb-1 NULL cc-2 NULL-10
bb-1 NULL cc-2 NULL-9
bb-1 NULL cc-2 NULL-8
bb-1 NULL cc-2 NULL-7
bb-1 NULL cc-2 NULL-6
bb-1 NULL cc-2 NULL-5
bb-1 NULL cc-2 NULL-4
bb-1 NULL cc-2 NULL-3
bb-1 NULL cc-2 NULL-2
bb-1 NULL cc-2 NULL-1
select * from t4 ignore index(idx1) where (a ='b-1' or a='bb-1') and b IS NULL and (c='c-1' or c='cc-2');
a b c filler
b-1 NULL c-1 NULL-15
b-1 NULL c-1 NULL-14
b-1 NULL c-1 NULL-13
b-1 NULL c-1 NULL-12
b-1 NULL c-1 NULL-11
b-1 NULL c-1 NULL-10
b-1 NULL c-1 NULL-9
b-1 NULL c-1 NULL-8
b-1 NULL c-1 NULL-7
b-1 NULL c-1 NULL-6
b-1 NULL c-1 NULL-5
b-1 NULL c-1 NULL-4
b-1 NULL c-1 NULL-3
b-1 NULL c-1 NULL-2
b-1 NULL c-1 NULL-1
bb-1 NULL cc-2 NULL-15
bb-1 NULL cc-2 NULL-14
bb-1 NULL cc-2 NULL-13
bb-1 NULL cc-2 NULL-12
bb-1 NULL cc-2 NULL-11
bb-1 NULL cc-2 NULL-10
bb-1 NULL cc-2 NULL-9
bb-1 NULL cc-2 NULL-8
bb-1 NULL cc-2 NULL-7
bb-1 NULL cc-2 NULL-6
bb-1 NULL cc-2 NULL-5
bb-1 NULL cc-2 NULL-4
bb-1 NULL cc-2 NULL-3
bb-1 NULL cc-2 NULL-2
bb-1 NULL cc-2 NULL-1
set @@read_rnd_buffer_size= @read_rnd_buffer_size_save;
drop table t1, t2, t3, t4;
CREATE TABLE t1 (
ID int(10) unsigned NOT NULL AUTO_INCREMENT,
col1 int(10) unsigned DEFAULT NULL,
key1 int(10) unsigned NOT NULL DEFAULT '0',
key2 int(10) unsigned DEFAULT NULL,
text1 text,
text2 text,
col2 smallint(6) DEFAULT '100',
col3 enum('headers','bodyandsubject') NOT NULL DEFAULT 'bodyandsubject',
col4 tinyint(3) unsigned NOT NULL DEFAULT '0',
PRIMARY KEY (ID),
KEY (key1),
KEY (key2)
) ENGINE=MyISAM AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
INSERT INTO t1 VALUES
(1,NULL,1130,NULL,'Hello',NULL,100,'bodyandsubject',0),
(2,NULL,1130,NULL,'bye',NULL,100,'bodyandsubject',0),
(3,NULL,1130,NULL,'red',NULL,100,'bodyandsubject',0),
(4,NULL,1130,NULL,'yellow',NULL,100,'bodyandsubject',0),
(5,NULL,1130,NULL,'blue',NULL,100,'bodyandsubject',0);
select * FROM t1 WHERE key1=1130 AND col1 IS NULL ORDER BY text1;
ID col1 key1 key2 text1 text2 col2 col3 col4
5 NULL 1130 NULL blue NULL 100 bodyandsubject 0
2 NULL 1130 NULL bye NULL 100 bodyandsubject 0
1 NULL 1130 NULL Hello NULL 100 bodyandsubject 0
3 NULL 1130 NULL red NULL 100 bodyandsubject 0
4 NULL 1130 NULL yellow NULL 100 bodyandsubject 0
drop table t1;
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