mirror of
https://github.com/MariaDB/server.git
synced 2025-01-18 21:12:26 +01:00
351 lines
7.3 KiB
Text
351 lines
7.3 KiB
Text
drop table if exists t1,t2,t3;
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CREATE TABLE t1 (id int,facility char(20));
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CREATE TABLE t2 (facility char(20));
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INSERT INTO t1 VALUES (NULL,NULL);
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INSERT INTO t1 VALUES (-1,'');
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INSERT INTO t1 VALUES (0,'');
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INSERT INTO t1 VALUES (1,'/L');
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INSERT INTO t1 VALUES (2,'A01');
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INSERT INTO t1 VALUES (3,'ANC');
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INSERT INTO t1 VALUES (4,'F01');
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INSERT INTO t1 VALUES (5,'FBX');
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INSERT INTO t1 VALUES (6,'MT');
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INSERT INTO t1 VALUES (7,'P');
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INSERT INTO t1 VALUES (8,'RV');
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INSERT INTO t1 VALUES (9,'SRV');
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INSERT INTO t1 VALUES (10,'VMT');
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INSERT INTO t2 SELECT DISTINCT FACILITY FROM t1;
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select id from t1 group by id;
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id
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NULL
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-1
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0
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1
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2
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3
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4
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5
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6
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7
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8
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9
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10
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select * from t1 order by id;
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id facility
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NULL NULL
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-1
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0
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1 /L
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2 A01
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3 ANC
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4 F01
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5 FBX
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6 MT
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7 P
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8 RV
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9 SRV
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10 VMT
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select id-5,facility from t1 order by "id-5";
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id-5 facility
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NULL NULL
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-6
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-5
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-4 /L
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-3 A01
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-2 ANC
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-1 F01
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0 FBX
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1 MT
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2 P
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3 RV
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4 SRV
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5 VMT
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select id,concat(facility) from t1 group by id ;
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id concat(facility)
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NULL NULL
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-1
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0
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1 /L
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2 A01
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3 ANC
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4 F01
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5 FBX
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6 MT
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7 P
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8 RV
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9 SRV
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10 VMT
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select id+0 as a,max(id),concat(facility) as b from t1 group by a order by b desc,a;
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a max(id) b
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NULL NULL NULL
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10 10 VMT
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9 9 SRV
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8 8 RV
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7 7 P
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6 6 MT
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5 5 FBX
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4 4 F01
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3 3 ANC
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2 2 A01
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1 1 /L
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-1 -1
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0 0
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select id >= 0 and id <= 5 as grp,count(*) from t1 group by grp;
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grp count(*)
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0 7
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1 6
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SELECT DISTINCT FACILITY FROM t1;
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FACILITY
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NULL
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/L
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A01
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ANC
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F01
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FBX
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MT
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P
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RV
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SRV
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VMT
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SELECT FACILITY FROM t2;
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FACILITY
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NULL
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/L
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A01
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ANC
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F01
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FBX
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MT
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P
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RV
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SRV
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VMT
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SELECT count(*) from t1,t2 where t1.facility=t2.facility;
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count(*)
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12
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select count(facility) from t1;
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count(facility)
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12
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select count(*) from t1;
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count(*)
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13
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select count(*) from t1 where facility IS NULL;
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count(*)
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1
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select count(*) from t1 where facility = NULL;
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count(*)
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0
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select count(*) from t1 where facility IS NOT NULL;
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count(*)
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12
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select count(*) from t1 where id IS NULL;
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count(*)
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1
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select count(*) from t1 where id IS NOT NULL;
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count(*)
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12
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drop table t1,t2;
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CREATE TABLE t1 (UserId int(11) DEFAULT '0' NOT NULL);
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INSERT INTO t1 VALUES (20);
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INSERT INTO t1 VALUES (27);
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SELECT UserId FROM t1 WHERE Userid=22;
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UserId
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SELECT UserId FROM t1 WHERE UserId=22 group by Userid;
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UserId
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SELECT DISTINCT UserId FROM t1 WHERE UserId=22 group by Userid;
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UserId
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SELECT DISTINCT UserId FROM t1 WHERE UserId=22;
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UserId
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drop table t1;
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CREATE TABLE t1 (a int(10) unsigned not null primary key,b int(10) unsigned);
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INSERT INTO t1 VALUES (1,1),(2,1);
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CREATE TABLE t2 (a int(10) unsigned not null, key (A));
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INSERT INTO t2 VALUES (1),(2);
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CREATE TABLE t3 (a int(10) unsigned, key(A), b text);
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INSERT INTO t3 VALUES (1,'1'),(2,'2');
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SELECT DISTINCT t3.b FROM t3,t2,t1 WHERE t3.a=t1.b AND t1.a=t2.a;
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b
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1
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INSERT INTO t2 values (1),(2),(3);
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INSERT INTO t3 VALUES (1,'1'),(2,'2'),(1,'1'),(2,'2');
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explain SELECT distinct t3.a FROM t3,t2,t1 WHERE t3.a=t1.b AND t1.a=t2.a;
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table type possible_keys key key_len ref rows Extra
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t3 index a a 5 NULL 6 Using index; Using temporary
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t2 index a a 4 NULL 5 Using index; Distinct
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t1 eq_ref PRIMARY PRIMARY 4 t2.a 1 where used; Distinct
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SELECT distinct t3.a FROM t3,t2,t1 WHERE t3.a=t1.b AND t1.a=t2.a;
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a
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1
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create temporary table t4 select * from t3;
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insert into t3 select * from t4;
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insert into t4 select * from t3;
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insert into t3 select * from t4;
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insert into t4 select * from t3;
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insert into t3 select * from t4;
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insert into t4 select * from t3;
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insert into t3 select * from t4;
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explain select distinct t1.a from t1,t3 where t1.a=t3.a;
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table type possible_keys key key_len ref rows Extra
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t1 index PRIMARY PRIMARY 4 NULL 2 Using index; Using temporary
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t3 ref a a 5 t1.a 10 Using index; Distinct
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select distinct t1.a from t1,t3 where t1.a=t3.a;
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a
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1
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2
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select distinct 1 from t1,t3 where t1.a=t3.a;
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1
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1
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drop table t1,t2,t3,t4;
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CREATE TABLE t1 (name varchar(255));
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INSERT INTO t1 VALUES ('aa'),('ab'),('ac'),('ad'),('ae');
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SELECT DISTINCT * FROM t1 LIMIT 2;
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name
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aa
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ab
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SELECT DISTINCT name FROM t1 LIMIT 2;
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name
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aa
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ab
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SELECT DISTINCT 1 FROM t1 LIMIT 2;
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1
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1
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drop table t1;
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CREATE TABLE t1 (
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ID int(11) NOT NULL auto_increment,
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NAME varchar(75) DEFAULT '' NOT NULL,
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LINK_ID int(11) DEFAULT '0' NOT NULL,
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PRIMARY KEY (ID),
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KEY NAME (NAME),
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KEY LINK_ID (LINK_ID)
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);
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INSERT INTO t1 (ID, NAME, LINK_ID) VALUES (1,'Mike',0),(2,'Jack',0),(3,'Bill',0);
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CREATE TABLE t2 (
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ID int(11) NOT NULL auto_increment,
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NAME varchar(150) DEFAULT '' NOT NULL,
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PRIMARY KEY (ID),
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KEY NAME (NAME)
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);
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SELECT DISTINCT
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t2.id AS key_link_id,
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t2.name AS link
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FROM t1
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LEFT JOIN t2 ON t1.link_id=t2.id
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GROUP BY t1.id
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ORDER BY link;
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key_link_id link
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NULL NULL
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drop table t1,t2;
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create table t1 (
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id int not null,
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name tinytext not null,
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unique (id)
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);
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create table t2 (
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id int not null,
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idx int not null,
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unique (id, idx)
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);
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create table t3 (
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id int not null,
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idx int not null,
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unique (id, idx)
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);
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insert into t1 values (1,'yes'), (2,'no');
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insert into t2 values (1,1);
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insert into t3 values (1,1);
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EXPLAIN
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SELECT DISTINCT
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t1.id
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from
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t1
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straight_join
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t2
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straight_join
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t3
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straight_join
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t1 as j_lj_t2 left join t2 as t2_lj
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on j_lj_t2.id=t2_lj.id
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straight_join
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t1 as j_lj_t3 left join t3 as t3_lj
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on j_lj_t3.id=t3_lj.id
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WHERE
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((t1.id=j_lj_t2.id AND t2_lj.id IS NULL) OR (t1.id=t2.id AND t2.idx=2))
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AND ((t1.id=j_lj_t3.id AND t3_lj.id IS NULL) OR (t1.id=t3.id AND t3.idx=2));
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table type possible_keys key key_len ref rows Extra
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t1 index id id 4 NULL 2 Using index; Using temporary
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t2 index id id 8 NULL 1 Using index; Distinct
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t3 index id id 8 NULL 1 Using index; Distinct
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j_lj_t2 index id id 4 NULL 2 where used; Using index; Distinct
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t2_lj index id id 8 NULL 1 where used; Using index; Distinct
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j_lj_t3 index id id 4 NULL 2 where used; Using index; Distinct
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t3_lj index id id 8 NULL 1 where used; Using index; Distinct
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SELECT DISTINCT
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t1.id
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from
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t1
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straight_join
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t2
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straight_join
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t3
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straight_join
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t1 as j_lj_t2 left join t2 as t2_lj
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on j_lj_t2.id=t2_lj.id
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straight_join
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t1 as j_lj_t3 left join t3 as t3_lj
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on j_lj_t3.id=t3_lj.id
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WHERE
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((t1.id=j_lj_t2.id AND t2_lj.id IS NULL) OR (t1.id=t2.id AND t2.idx=2))
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AND ((t1.id=j_lj_t3.id AND t3_lj.id IS NULL) OR (t1.id=t3.id AND t3.idx=2));
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id
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2
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drop table t1,t2,t3;
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drop table if exists t1;
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create table t1 (a int not null, b int not null, t time);
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insert into t1 values (1,1,"00:06:15"),(1,2,"00:06:15"),(1,2,"00:30:15"),(1,3,"00:06:15"),(1,3,"00:30:15");
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select a,sec_to_time(sum(time_to_sec(t))) from t1 group by a,b;
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a sec_to_time(sum(time_to_sec(t)))
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1 00:06:15
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1 00:36:30
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1 00:36:30
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select distinct a,sec_to_time(sum(time_to_sec(t))) from t1 group by a,b;
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a sec_to_time(sum(time_to_sec(t)))
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1 00:06:15
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1 00:36:30
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create table t2 (a int not null primary key, b int);
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insert into t2 values (1,1),(2,2),(3,3);
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select t1.a,sec_to_time(sum(time_to_sec(t))) from t1 left join t2 on (t1.b=t2.a) group by t1.a,t2.b;
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a sec_to_time(sum(time_to_sec(t)))
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1 00:06:15
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1 00:36:30
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1 00:36:30
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select distinct t1.a,sec_to_time(sum(time_to_sec(t))) from t1 left join t2 on (t1.b=t2.a) group by t1.a,t2.b;
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a sec_to_time(sum(time_to_sec(t)))
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1 00:06:15
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1 00:36:30
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drop table t1,t2;
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create table t1 (a int not null,b char(5), c text);
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insert into t1 (a) values (1),(2),(3),(4),(1),(2),(3),(4);
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select distinct a from t1 group by b,a having a > 2 order by a desc;
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a
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4
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3
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select distinct a,c from t1 group by b,c,a having a > 2 order by a desc;
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a c
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4 NULL
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3 NULL
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drop table t1;
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create table t1 (a char(1), key(a)) type=myisam;
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insert into t1 values('1'),('1');
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select * from t1 where a >= '1';
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a
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1
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1
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select distinct a from t1 order by a desc;
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a
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1
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select distinct a from t1 where a >= '1' order by a desc;
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a
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1
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drop table t1;
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