215 lines
6.8 KiB
Plaintext
215 lines
6.8 KiB
Plaintext
drop table if exists t1,t2;
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create table t1 (pk int primary key, grp int, a int, c char(10) not null);
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insert into t1 values (1, 1,1,'a');
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insert into t1 values (2, 2,2,'b');
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insert into t1 values (3, 2,3,'c');
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insert into t1 values (4, 3,4,'E');
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insert into t1 values (5, 3,5,'C');
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insert into t1 values (6, 3,6,'D');
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select a,c,sum(a) from t1 group by a order by a;
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a c sum(a)
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1 a 1
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2 b 2
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3 c 3
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4 E 4
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5 C 5
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6 D 6
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select a,c,sum(a) from t1 where a > 10 group by a order by a;
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a c sum(a)
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select sum(a) from t1 where a > 10;
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sum(a)
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NULL
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select count(distinct a),count(distinct grp) from t1;
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count(distinct a) count(distinct grp)
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6 3
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insert into t1 values (7, null,null,'');
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select count(distinct a),count(distinct grp) from t1;
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count(distinct a) count(distinct grp)
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6 3
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create table t2 (pk int primary key, grp int, a int, c char(10));
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select grp,max(a)+max(grp),max(c) from t1 group by grp order by grp;
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grp max(a)+max(grp) max(c)
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NULL NULL
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1 2 a
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2 5 c
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3 9 E
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select * from t2;
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pk grp a c
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drop table t1,t2;
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drop table if exists t1;
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CREATE TABLE t1 (id int ,value1 decimal(10,2),c int primary key);
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INSERT INTO t1 VALUES (1,0.00,1),(1,1.00,2), (1,2.00,3), (2,10.00,4), (2,11.00,5), (2,12.00,6);
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CREATE TABLE t2 (id int primary key,name char(20));
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INSERT INTO t2 VALUES (1,'Set One'),(2,'Set Two');
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select id, avg(value1) from t1 group by id;
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id avg(value1)
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1 1.000000
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2 11.000000
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select name, avg(value1) from t1, t2 where t1.id = t2.id group by t1.id;
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name avg(value1)
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Set One 1.000000
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Set Two 11.000000
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drop table t1,t2;
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create table t1 (pk int primary key, id int not null);
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create table t2 (pk int primary key, id int not null,rating int null);
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insert into t1 values(1,1),(2,2),(3,3);
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insert into t2 values(1, 1, 3),(2, 2, NULL),(3, 2, NULL),(4, 3, 2),(5, 3, NULL);
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select t1.id, avg(rating) from t1 left join t2 on ( t1.id = t2.id ) group by t1.id order by t1.id;
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id avg(rating)
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1 3.0000
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2 NULL
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3 2.0000
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drop table t1,t2;
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create table t1 (a int primary key, c char(10), b char(128));
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INSERT INTO t1 VALUES (1,'1','1');
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INSERT INTO t1 VALUES (2,'2','2');
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INSERT INTO t1 VALUES (4,'4','4');
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select count(*) from t1;
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count(*)
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3
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select count(*) from t1 where a = 1;
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count(*)
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1
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select count(*) from t1 where a = 100;
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count(*)
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0
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select count(*) from t1 where a >= 10;
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count(*)
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0
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select count(a) from t1 where a = 1;
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count(a)
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1
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select count(a) from t1 where a = 100;
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count(a)
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0
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select count(a) from t1 where a >= 10;
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count(a)
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0
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select count(b) from t1 where b >= 2;
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count(b)
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2
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select count(b) from t1 where b >= 10;
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count(b)
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0
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select count(c) from t1 where c = 10;
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count(c)
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0
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drop table t1;
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CREATE TABLE t1 (d datetime default now(), i int primary key);
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INSERT INTO t1(i) VALUES (1);
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SELECT COUNT(i), i, COUNT(i)*i FROM t1 GROUP BY i;
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COUNT(i) i COUNT(i)*i
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1 1 1
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SELECT COUNT(i), (i+0), COUNT(i)*(i+0) FROM t1 GROUP BY i;
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COUNT(i) (i+0) COUNT(i)*(i+0)
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1 1 1
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DROP TABLE t1;
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create table t1 (
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pk int primary key,
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num float,
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my_user char(20)
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);
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insert into t1 values (1, 10.3,'nem'),(2, 20.53,'monty'),(3, 30.23,'sinisa');
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insert into t1 values (4, 30.13,'nem'),(5, 20.98,'monty'),(6, 10.45,'sinisa');
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insert into t1 values (7, 5.2,'nem'),(8, 8.64,'monty'),(9, 11.12,'sinisa');
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select sum(num) from t1;
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sum(num)
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147.57999897003174
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select sum(num) from t1 group by my_user order by my_user;
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sum(num)
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50.15000057220459
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45.6299991607666
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51.79999923706055
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drop table t1;
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drop table if exists t1,t2,t3;
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create table t1 (pk int primary key, a1 int, a2 char(3));
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insert into t1 values(1, 10,'aaa'), (2, 10,null), (3, 10,'bbb'), (4, 20,'zzz');
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create table t2(pk int primary key, a1 char(3), a2 int, a3 float);
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create table t3(pk int primary key, a1 char(3), a2 int, a3 float);
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select * from t1;
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pk a1 a2
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1 10 aaa
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2 10 NULL
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3 10 bbb
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4 20 zzz
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select min(a2) from t1;
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min(a2)
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aaa
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select max(t1.a1), max(t2.a2) from t1, t2;
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max(t1.a1) max(t2.a2)
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NULL NULL
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insert into t2 values(1, 'AAA', 10, 0.5);
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insert into t2 values(2, 'BBB', 20, 1.0);
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select t1.a1, t1.a2, t2.a1, t2.a2 from t1 left outer join t3 on t1.a1=10;
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ERROR 42S22: Unknown column 't2.a1' in 'field list'
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select max(t1.a2) from t1 left outer join t2 on t1.a1=10;
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max(t1.a2)
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zzz
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select max(t2.a1) from t1 left outer join t2 on t1.pk=t2.pk and 1=0 where t2.a1='AAA';
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max(t2.a1)
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NULL
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explain select max(t2.a1) from t1 left outer join t2 on t1.pk=t2.pk and 1=0 where t2.a1='AAA';
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select max(t2.a1) from t1 left outer join t2 on t1.a2=t2.a1 where t2.a1='AAA';
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max(t2.a1)
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AAA
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explain select max(t2.a1) from t1 left outer join t2 on t1.a2=t2.a1 where t2.a1='AAA';
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select max(t2.a1) from t1 left outer join t2 on t1.pk=t2.pk where t2.a1='AAA' and 1=0;
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max(t2.a1)
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NULL
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explain select max(t2.a1) from t1 left outer join t2 on t1.pk=t2.pk where t2.a1='AAA' and 1=0;
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select max(t1.a2),max(t2.a1) from t1 left outer join t2 on t1.pk=t2.pk and t1.a1=10;
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max(t1.a2) max(t2.a1)
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zzz BBB
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explain select max(t1.a2),max(t2.a1) from t1 left outer join t2 on t1.pk=t2.pk and t1.a1=10;
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select max(t1.a2),max(t2.a1) from t1 left outer join t2 on t1.pk=t2.pk and t1.pk=10;
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max(t1.a2) max(t2.a1)
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zzz NULL
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explain select max(t1.a2),max(t2.a1) from t1 left outer join t2 on t1.pk=t2.pk and t1.pk=10;
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select * from t1 left join t2 on t1.pk=t2.pk where t2.a2 > 1 and t2.a2 < 10;
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pk a1 a2 pk a1 a2 a3
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explain select * from t1 left join t2 on t1.pk=t2.pk where t2.a2 > 1 and t2.a2 < 10;
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select * from t1 left join t2 on t1.pk=t2.pk and t2.a2 > 1 and t2.a2 < 10 order by t1.pk;
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pk a1 a2 pk a1 a2 a3
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1 10 aaa NULL NULL NULL NULL
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2 10 NULL NULL NULL NULL NULL
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3 10 bbb NULL NULL NULL NULL
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4 20 zzz NULL NULL NULL NULL
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explain select * from t1 left join t2 on t1.pk=t2.pk and t2.a2 > 1 and t2.a2 < 10;
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drop table t1,t2;
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CREATE TABLE t1 (pk int primary key, a int, b int);
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select count(b), sum(b), avg(b), min(b), max(b) from t1;
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count(b) sum(b) avg(b) min(b) max(b)
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0 NULL NULL NULL NULL
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select a,count(b), sum(b), avg(b), min(b), max(b) from t1 group by a order by a;
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a count(b) sum(b) avg(b) min(b) max(b)
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insert into t1 values (1, 1,null);
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select a,count(b), sum(b), avg(b), min(b), max(b) from t1 group by a order by a;
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a count(b) sum(b) avg(b) min(b) max(b)
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1 0 NULL NULL NULL NULL
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insert into t1 values (2, 1,null);
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insert into t1 values (3, 2,null);
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select a,count(b), sum(b), avg(b), min(b), max(b) from t1 group by a order by a;
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a count(b) sum(b) avg(b) min(b) max(b)
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1 0 NULL NULL NULL NULL
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2 0 NULL NULL NULL NULL
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insert into t1 values (4, 2,1);
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select a,count(b), sum(b), avg(b), min(b), max(b) from t1 group by a order by a;
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a count(b) sum(b) avg(b) min(b) max(b)
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1 0 NULL NULL NULL NULL
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2 1 1 1.0000 1 1
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insert into t1 values (5, 3,1);
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select a,count(b), sum(b), avg(b), min(b), max(b) from t1 group by a order by a;
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a count(b) sum(b) avg(b) min(b) max(b)
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1 0 NULL NULL NULL NULL
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2 1 1 1.0000 1 1
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3 1 1 1.0000 1 1
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drop table t1;
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create table t1 (col int primary key,col2 int);
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insert into t1(col) values (-1), (-2), (-3);
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drop table t1;
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create table t1 (a int primary key,b int);
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select avg(2) from t1;
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avg(2)
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NULL
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drop table t1;
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