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https://github.com/MariaDB/server.git
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89 lines
2.4 KiB
Plaintext
89 lines
2.4 KiB
Plaintext
drop table if exists t1;
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select IF(0,"ERROR","this"),IF(1,"is","ERROR"),IF(NULL,"ERROR","a"),IF(1,2,3)|0,IF(1,2.0,3.0)+0 ;
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IF(0,"ERROR","this") IF(1,"is","ERROR") IF(NULL,"ERROR","a") IF(1,2,3)|0 IF(1,2.0,3.0)+0
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this is a 2 2.0
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CREATE TABLE t1 (st varchar(255) NOT NULL, u int(11) NOT NULL) ENGINE=MyISAM;
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INSERT INTO t1 VALUES ('a',1),('A',1),('aa',1),('AA',1),('a',1),('aaa',0),('BBB',0);
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select if(1,st,st) s from t1 order by s;
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s
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a
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A
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a
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aa
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AA
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aaa
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BBB
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select if(u=1,st,st) s from t1 order by s;
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s
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a
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A
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a
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aa
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AA
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aaa
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BBB
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select if(u=1,binary st,st) s from t1 order by s;
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s
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A
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AA
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BBB
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a
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a
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aa
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aaa
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select if(u=1,st,binary st) s from t1 where st like "%a%" order by s;
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s
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A
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AA
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a
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a
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aa
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aaa
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explain extended select if(u=1,st,binary st) s from t1 where st like "%a%" order by s;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 7 Using where; Using filesort
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Warnings:
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Note 1003 select if((`test`.`t1`.`u` = 1),`test`.`t1`.`st`,cast(`test`.`t1`.`st` as char charset binary)) AS `s` from `test`.`t1` where (`test`.`t1`.`st` like _latin1'%a%') order by if((`test`.`t1`.`u` = 1),`test`.`t1`.`st`,cast(`test`.`t1`.`st` as char charset binary))
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select nullif(u=0, 'test') from t1;
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nullif(u=0, 'test')
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NULL
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NULL
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NULL
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NULL
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NULL
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1
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1
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explain extended select nullif(u=0, 'test') from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 7
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Warnings:
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Note 1003 select nullif((`test`.`t1`.`u` = 0),_latin1'test') AS `nullif(u=0, 'test')` from `test`.`t1`
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drop table t1;
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select NULLIF(NULL,NULL), NULLIF(NULL,1), NULLIF(NULL,1.0), NULLIF(NULL,"test");
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NULLIF(NULL,NULL) NULLIF(NULL,1) NULLIF(NULL,1.0) NULLIF(NULL,"test")
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NULL NULL NULL NULL
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select NULLIF(1,NULL), NULLIF(1.0, NULL), NULLIF("test", NULL);
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NULLIF(1,NULL) NULLIF(1.0, NULL) NULLIF("test", NULL)
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1 1.0 test
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create table t1 (num double(12,2));
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insert into t1 values (144.54);
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select sum(if(num is null,0.00,num)) from t1;
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sum(if(num is null,0.00,num))
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144.54
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drop table t1;
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create table t1 (x int, y int);
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insert into t1 values (0,6),(10,16),(20,26),(30,10),(40,46),(50,56);
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select min(if(y -x > 5,y,NULL)), max(if(y - x > 5,y,NULL)) from t1;
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min(if(y -x > 5,y,NULL)) max(if(y - x > 5,y,NULL))
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6 56
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drop table t1;
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create table t1 (a int);
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insert t1 values (1),(2);
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select if(1>2,a,avg(a)) from t1;
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if(1>2,a,avg(a))
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1.5000
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drop table t1;
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SELECT NULLIF(5,5) IS NULL, NULLIF(5,5) IS NOT NULL;
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NULLIF(5,5) IS NULL NULLIF(5,5) IS NOT NULL
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1 0
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