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https://github.com/MariaDB/server.git
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134 lines
3.7 KiB
Plaintext
134 lines
3.7 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 filtered Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 7 100.00 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, 1) from t1;
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nullif(u, 1)
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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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0
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0
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explain extended select nullif(u, 1) from t1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 7 100.00
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Warnings:
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Note 1003 select nullif(`test`.`t1`.`u`,1) AS `nullif(u, 1)` from `test`.`t1`
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drop table t1;
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select nullif(1,'test');
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nullif(1,'test')
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1
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Warnings:
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Warning 1292 Truncated incorrect DOUBLE value: 'test'
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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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CREATE TABLE `t1` (
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`id` int(11) NOT NULL ,
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`date` int(10) default NULL,
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`text` varchar(32) NOT NULL
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);
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INSERT INTO t1 VALUES (1,1110000000,'Day 1'),(2,1111000000,'Day 2'),(3,1112000000,'Day 3');
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SELECT id, IF(date IS NULL, '-', FROM_UNIXTIME(date, '%d-%m-%Y')) AS date_ord, text FROM t1 ORDER BY date_ord ASC;
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id date_ord text
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1 05-03-2005 Day 1
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2 16-03-2005 Day 2
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3 28-03-2005 Day 3
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SELECT id, IF(date IS NULL, '-', FROM_UNIXTIME(date, '%d-%m-%Y')) AS date_ord, text FROM t1 ORDER BY date_ord DESC;
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id date_ord text
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3 28-03-2005 Day 3
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2 16-03-2005 Day 2
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1 05-03-2005 Day 1
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DROP TABLE t1;
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CREATE TABLE t1 (a CHAR(10));
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INSERT INTO t1 VALUES ('aaa'), (NULL), (''), ('bbb');
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SELECT a, NULLIF(a,'') FROM t1;
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a NULLIF(a,'')
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aaa aaa
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NULL NULL
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NULL
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bbb bbb
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SELECT a, NULLIF(a,'') FROM t1 WHERE NULLIF(a,'') IS NULL;
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a NULLIF(a,'')
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NULL NULL
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NULL
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DROP TABLE t1;
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create table t1 (f1 int, f2 int);
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insert into t1 values(1,1),(0,0);
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select f1, f2, if(f1, 40.0, 5.00) from t1 group by f1 order by f2;
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f1 f2 if(f1, 40.0, 5.00)
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0 0 5.00
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1 1 40.00
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drop table t1;
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select if(0, 18446744073709551610, 18446744073709551610);
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if(0, 18446744073709551610, 18446744073709551610)
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18446744073709551610
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