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|
drop table if exists t1,t2;
set @sav_dpi= @@div_precision_increment;
set div_precision_increment= 5;
show variables like 'div_precision_increment';
Variable_name Value
div_precision_increment 5
create table t1 (grp int, a bigint, c char(10) not null);
insert into t1 values (1,1,"a");
insert into t1 values (2,2,"b");
insert into t1 values (2,3,"c");
insert into t1 values (3,4,"E");
insert into t1 values (3,5,"C");
insert into t1 values (3,6,"D");
select a,c,sum(a) from t1 group by a;
a c sum(a)
1 a 1
2 b 2
3 c 3
4 E 4
5 C 5
6 D 6
select a,c,sum(a) from t1 where a > 10 group by a;
a c sum(a)
select sum(a) from t1 where a > 10;
sum(a)
NULL
select a from t1 order by rand(10);
a
2
6
1
3
5
4
select distinct a from t1 order by rand(10);
a
2
6
1
3
5
4
select count(distinct a),count(distinct grp) from t1;
count(distinct a) count(distinct grp)
6 3
insert into t1 values (null,null,'');
select count(distinct a),count(distinct grp) from t1;
count(distinct a) count(distinct grp)
6 3
create table t2 (grp int, a bigint, c char(10));
insert into t2 select grp,max(a)+max(grp),max(c) from t1 group by grp;
replace into t2 select grp, a, c from t1 limit 2,1;
select * from t2;
grp a c
NULL NULL
1 2 a
2 5 c
3 9 E
2 3 c
drop table t1,t2;
CREATE TABLE t1 (id int,value1 float(10,2));
INSERT INTO t1 VALUES (1,0.00),(1,1.00), (1,2.00), (2,10.00), (2,11.00), (2,12.00);
CREATE TABLE t2 (id int,name char(20));
INSERT INTO t2 VALUES (1,'Set One'),(2,'Set Two');
select id, avg(value1), std(value1), variance(value1) from t1 group by id;
id avg(value1) std(value1) variance(value1)
1 1.0000000 0.816497 0.666667
2 11.0000000 0.816497 0.666667
select name, avg(value1), std(value1), variance(value1) from t1, t2 where t1.id = t2.id group by t1.id;
name avg(value1) std(value1) variance(value1)
Set One 1.0000000 0.816497 0.666667
Set Two 11.0000000 0.816497 0.666667
drop table t1,t2;
create table t1 (id int not null);
create table t2 (id int not null,rating int null);
insert into t1 values(1),(2),(3);
insert into t2 values(1, 3),(2, NULL),(2, NULL),(3, 2),(3, NULL);
select t1.id, avg(rating) from t1 left join t2 on ( t1.id = t2.id ) group by t1.id;
id avg(rating)
1 3.00000
2 NULL
3 2.00000
select sql_small_result t2.id, avg(rating) from t2 group by t2.id;
id avg(rating)
1 3.00000
2 NULL
3 2.00000
select sql_big_result t2.id, avg(rating) from t2 group by t2.id;
id avg(rating)
1 3.00000
2 NULL
3 2.00000
select sql_small_result t2.id, avg(rating+0.0e0) from t2 group by t2.id;
id avg(rating+0.0e0)
1 3
2 NULL
3 2
select sql_big_result t2.id, avg(rating+0.0e0) from t2 group by t2.id;
id avg(rating+0.0e0)
1 3
2 NULL
3 2
drop table t1,t2;
create table t1 (a int primary key, c char(10), b text);
INSERT INTO t1 VALUES (1,'1','1');
INSERT INTO t1 VALUES (2,'2','2');
INSERT INTO t1 VALUES (4,'4','4');
select count(*) from t1;
count(*)
3
select count(*) from t1 where a = 1;
count(*)
1
select count(*) from t1 where a = 100;
count(*)
0
select count(*) from t1 where a >= 10;
count(*)
0
select count(a) from t1 where a = 1;
count(a)
1
select count(a) from t1 where a = 100;
count(a)
0
select count(a) from t1 where a >= 10;
count(a)
0
select count(b) from t1 where b >= 2;
count(b)
2
select count(b) from t1 where b >= 10;
count(b)
0
select count(c) from t1 where c = 10;
count(c)
0
drop table t1;
CREATE TABLE t1 (d DATETIME, i INT);
INSERT INTO t1 VALUES (NOW(), 1);
SELECT COUNT(i), i, COUNT(i)*i FROM t1 GROUP BY i;
COUNT(i) i COUNT(i)*i
1 1 1
SELECT COUNT(i), (i+0), COUNT(i)*(i+0) FROM t1 GROUP BY i;
COUNT(i) (i+0) COUNT(i)*(i+0)
1 1 1
DROP TABLE t1;
create table t1 (
num float(5,2),
user char(20)
);
insert into t1 values (10.3,'nem'),(20.53,'monty'),(30.23,'sinisa');
insert into t1 values (30.13,'nem'),(20.98,'monty'),(10.45,'sinisa');
insert into t1 values (5.2,'nem'),(8.64,'monty'),(11.12,'sinisa');
select sum(num) from t1;
sum(num)
147.58
select sum(num) from t1 group by user;
sum(num)
50.15
45.63
51.80
drop table t1;
create table t1 (a1 int, a2 char(3), key k1(a1), key k2(a2));
insert into t1 values(10,'aaa'), (10,null), (10,'bbb'), (20,'zzz');
create table t2(a1 char(3), a2 int, a3 real, key k1(a1), key k2(a2, a1));
select * from t1;
a1 a2
10 aaa
10 NULL
10 bbb
20 zzz
select min(a2) from t1;
min(a2)
aaa
select max(t1.a1), max(t2.a2) from t1, t2;
max(t1.a1) max(t2.a2)
NULL NULL
select max(t1.a1) from t1, t2;
max(t1.a1)
NULL
select max(t2.a2), max(t1.a1) from t1, t2;
max(t2.a2) max(t1.a1)
NULL NULL
explain select min(a2) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
explain select max(t1.a1), max(t2.a2) from t1, t2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL No matching min/max row
insert into t2 values('AAA', 10, 0.5);
insert into t2 values('BBB', 20, 1.0);
select t1.a1, t1.a2, t2.a1, t2.a2 from t1,t2;
a1 a2 a1 a2
10 NULL AAA 10
10 NULL BBB 20
10 aaa AAA 10
10 aaa BBB 20
10 bbb AAA 10
10 bbb BBB 20
20 zzz AAA 10
20 zzz BBB 20
select max(t1.a1), max(t2.a1) from t1, t2 where t2.a2=9;
max(t1.a1) max(t2.a1)
NULL NULL
select max(t2.a1), max(t1.a1) from t1, t2 where t2.a2=9;
max(t2.a1) max(t1.a1)
NULL NULL
select t1.a1, t1.a2, t2.a1, t2.a2 from t1 left outer join t2 on t1.a1=10;
a1 a2 a1 a2
10 aaa AAA 10
10 aaa BBB 20
10 NULL AAA 10
10 NULL BBB 20
10 bbb AAA 10
10 bbb BBB 20
20 zzz NULL NULL
select max(t1.a2) from t1 left outer join t2 on t1.a1=10;
max(t1.a2)
zzz
select max(t2.a1) from t2 left outer join t1 on t2.a2=10 where t2.a2=20;
max(t2.a1)
BBB
select max(t2.a1) from t2 left outer join t1 on t2.a2=10 where t2.a2=10;
max(t2.a1)
AAA
select max(t2.a1) from t1 left outer join t2 on t1.a2=t2.a1 and 1=0 where t2.a1='AAA';
max(t2.a1)
NULL
select max(t1.a2),max(t2.a1) from t1 left outer join t2 on t1.a1=10;
max(t1.a2) max(t2.a1)
zzz BBB
drop table t1,t2;
create table t1 (a int);
select avg(2) from t1;
avg(2)
NULL
drop table t1;
create table t1(
a1 char(3) primary key,
a2 int,
a3 char(3),
a4 real,
a5 date,
key k1(a2,a3),
key k2(a4 desc,a1),
key k3(a5,a1)
);
create table t2(
a1 char(3) primary key,
a2 char(17),
a3 char(2),
a4 char(3),
key k1(a3, a2),
key k2(a4)
);
insert into t1 values('AME',0,'SEA',0.100,date'1942-02-19');
insert into t1 values('HBR',1,'SEA',0.085,date'1948-03-05');
insert into t1 values('BOT',2,'SEA',0.085,date'1951-11-29');
insert into t1 values('BMC',3,'SEA',0.085,date'1958-09-08');
insert into t1 values('TWU',0,'LAX',0.080,date'1969-10-05');
insert into t1 values('BDL',0,'DEN',0.080,date'1960-11-27');
insert into t1 values('DTX',1,'NYC',0.080,date'1961-05-04');
insert into t1 values('PLS',1,'WDC',0.075,date'1949-01-02');
insert into t1 values('ZAJ',2,'CHI',0.075,date'1960-06-15');
insert into t1 values('VVV',2,'MIN',0.075,date'1959-06-28');
insert into t1 values('GTM',3,'DAL',0.070,date'1977-09-23');
insert into t1 values('SSJ',null,'CHI',null,date'1974-03-19');
insert into t1 values('KKK',3,'ATL',null,null);
insert into t1 values('XXX',null,'MIN',null,null);
insert into t1 values('WWW',1,'LED',null,null);
insert into t2 values('TKF','Seattle','WA','AME');
insert into t2 values('LCC','Los Angeles','CA','TWU');
insert into t2 values('DEN','Denver','CO','BDL');
insert into t2 values('SDC','San Diego','CA','TWU');
insert into t2 values('NOL','New Orleans','LA','GTM');
insert into t2 values('LAK','Los Angeles','CA','TWU');
insert into t2 values('AAA','AAA','AA','AME');
select * from t1;
a1 a2 a3 a4 a5
AME 0 SEA 0.1 1942-02-19
BDL 0 DEN 0.08 1960-11-27
BMC 3 SEA 0.085 1958-09-08
BOT 2 SEA 0.085 1951-11-29
DTX 1 NYC 0.08 1961-05-04
GTM 3 DAL 0.07 1977-09-23
HBR 1 SEA 0.085 1948-03-05
KKK 3 ATL NULL NULL
PLS 1 WDC 0.075 1949-01-02
SSJ NULL CHI NULL 1974-03-19
TWU 0 LAX 0.08 1969-10-05
VVV 2 MIN 0.075 1959-06-28
WWW 1 LED NULL NULL
XXX NULL MIN NULL NULL
ZAJ 2 CHI 0.075 1960-06-15
select * from t2;
a1 a2 a3 a4
AAA AAA AA AME
DEN Denver CO BDL
LAK Los Angeles CA TWU
LCC Los Angeles CA TWU
NOL New Orleans LA GTM
SDC San Diego CA TWU
TKF Seattle WA AME
explain
select min(a1) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(a1) from t1;
min(a1)
AME
explain
select max(a4) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select max(a4) from t1;
max(a4)
0.1
explain
select min(a5), max(a5) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(a5), max(a5) from t1;
min(a5) max(a5)
1942-02-19 1977-09-23
explain
select min(a3) from t1 where a2 = 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(a3) from t1 where a2 = 2;
min(a3)
CHI
explain
select min(a1), max(a1) from t1 where a4 = 0.080;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(a1), max(a1) from t1 where a4 = 0.080;
min(a1) max(a1)
BDL TWU
explain
select min(t1.a5), max(t2.a3) from t1, t2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(t1.a5), max(t2.a3) from t1, t2;
min(t1.a5) max(t2.a3)
1942-02-19 WA
explain
select min(t1.a3), max(t2.a2) from t1, t2 where t1.a2 = 0 and t2.a3 = 'CA';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(t1.a3), max(t2.a2) from t1, t2 where t1.a2 = 0 and t2.a3 = 'CA';
min(t1.a3) max(t2.a2)
DEN San Diego
explain
select min(a1) from t1 where a1 > 'KKK';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(a1) from t1 where a1 > 'KKK';
min(a1)
PLS
explain
select min(a1) from t1 where a1 >= 'KKK';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(a1) from t1 where a1 >= 'KKK';
min(a1)
KKK
explain
select max(a3) from t1 where a2 = 2 and a3 < 'SEA';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select max(a3) from t1 where a2 = 2 and a3 < 'SEA';
max(a3)
MIN
explain
select max(a5) from t1 where a5 < date'1970-01-01';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select max(a5) from t1 where a5 < date'1970-01-01';
max(a5)
1969-10-05
explain
select max(a3) from t1 where a2 is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select max(a3) from t1 where a2 is null;
max(a3)
MIN
explain
select max(a3) from t1 where a2 = 0 and a3 between 'K' and 'Q';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select max(a3) from t1 where a2 = 0 and a3 between 'K' and 'Q';
max(a3)
LAX
explain
select min(a1), max(a1) from t1 where a1 between 'A' and 'P';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(a1), max(a1) from t1 where a1 between 'A' and 'P';
min(a1) max(a1)
AME KKK
explain
select max(a3) from t1 where a3 < 'SEA' and a2 = 2 and a3 <= 'MIN';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select max(a3) from t1 where a3 < 'SEA' and a2 = 2 and a3 <= 'MIN';
max(a3)
MIN
explain
select max(a3) from t1 where a3 = 'MIN' and a2 = 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select max(a3) from t1 where a3 = 'MIN' and a2 = 2;
max(a3)
MIN
explain
select max(a3) from t1 where a3 = 'DEN' and a2 = 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL No matching min/max row
select max(a3) from t1 where a3 = 'DEN' and a2 = 2;
max(a3)
NULL
explain
select max(t1.a3), min(t2.a2) from t1, t2 where t1.a2 = 2 and t1.a3 < 'MIN' and t2.a3 = 'CA';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select max(t1.a3), min(t2.a2) from t1, t2 where t1.a2 = 2 and t1.a3 < 'MIN' and t2.a3 = 'CA';
max(t1.a3) min(t2.a2)
CHI Los Angeles
explain
select max(a3) from t1 where a2 is null and a2 = 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
select max(a3) from t1 where a2 is null and a2 = 2;
max(a3)
NULL
explain
select max(a2) from t1 where a2 >= 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select max(a2) from t1 where a2 >= 1;
max(a2)
3
explain
select min(a3) from t1 where a2 = 2 and a3 < 'SEA';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(a3) from t1 where a2 = 2 and a3 < 'SEA';
min(a3)
CHI
explain
select min(a3) from t1 where a2 = 4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL No matching min/max row
select min(a3) from t1 where a2 = 4;
min(a3)
NULL
explain
select min(a3) from t1 where a2 = 2 and a3 > 'SEA';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL No matching min/max row
select min(a3) from t1 where a2 = 2 and a3 > 'SEA';
min(a3)
NULL
explain
select (min(a4)+max(a4))/2 from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select (min(a4)+max(a4))/2 from t1;
(min(a4)+max(a4))/2
0.085
explain
select min(a3) from t1 where 2 = a2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(a3) from t1 where 2 = a2;
min(a3)
CHI
explain
select max(a3) from t1 where a2 = 2 and 'SEA' > a3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select max(a3) from t1 where a2 = 2 and 'SEA' > a3;
max(a3)
MIN
explain
select max(a3) from t1 where a2 = 2 and 'SEA' < a3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL No matching min/max row
select max(a3) from t1 where a2 = 2 and 'SEA' < a3;
max(a3)
NULL
explain
select min(a3) from t1 where a2 = 2 and a3 >= 'CHI';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(a3) from t1 where a2 = 2 and a3 >= 'CHI';
min(a3)
CHI
explain
select min(a3) from t1 where a2 = 2 and a3 >= 'CHI' and a3 < 'SEA';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(a3) from t1 where a2 = 2 and a3 >= 'CHI' and a3 < 'SEA';
min(a3)
CHI
explain
select min(a3) from t1 where a2 = 2 and a3 >= 'CHI' and a3 = 'MIN';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(a3) from t1 where a2 = 2 and a3 >= 'CHI' and a3 = 'MIN';
min(a3)
MIN
explain
select min(a3) from t1 where a2 = 2 and a3 >= 'SEA' and a3 = 'MIN';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
select min(a3) from t1 where a2 = 2 and a3 >= 'SEA' and a3 = 'MIN';
min(a3)
NULL
explain
select min(t1.a1), min(t2.a4) from t1,t2 where t1.a1 < 'KKK' and t2.a4 < 'KKK';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
select min(t1.a1), min(t2.a4) from t1,t2 where t1.a1 < 'KKK' and t2.a4 < 'KKK';
min(t1.a1) min(t2.a4)
AME AME
explain
select min(a1) from t1 where a1 > 'KKK' or a1 < 'XXX';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range PRIMARY PRIMARY 0 NULL 7 Using where; Using index
explain
select min(a1) from t1 where a1 != 'KKK';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index PRIMARY PRIMARY 14 NULL 15 Using where; Using index
explain
select max(a3) from t1 where a2 < 2 and a3 < 'SEA';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range k1 k1 5 NULL 6 Using where; Using index
explain
select max(t1.a3), min(t2.a2) from t1, t2 where t1.a2 = 2 and t1.a3 < 'MIN' and t2.a3 > 'CA';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range k1 k1 20 NULL 1 Using where; Using index
1 SIMPLE t2 range k1 k1 11 NULL 3 Using where; Using index; Using join buffer
explain
select min(a4 - 0.01) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL PRIMARY 14 NULL 15
explain
select max(a4 + 0.01) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL PRIMARY 14 NULL 15
explain
select min(a3) from t1 where (a2 +1 ) is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL PRIMARY 14 NULL 15 Using where
explain
select min(a3) from t1 where (a2 + 1) = 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL PRIMARY 14 NULL 15 Using where
explain
select min(a3) from t1 where 2 = (a2 + 1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL PRIMARY 14 NULL 15 Using where
explain
select min(a2) from t1 where a2 < 2 * a2 - 8;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL PRIMARY 14 NULL 15 Using where
explain
select min(a1) from t1 where a1 between a3 and 'KKK';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index PRIMARY PRIMARY 14 NULL 15 Using where
explain
select min(a4) from t1 where (a4 + 0.01) between 0.07 and 0.08;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL PRIMARY 14 NULL 15 Using where
explain
select concat(min(t1.a1),min(t2.a4)) from t1, t2 where t2.a4 <> 'AME';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index k2 PRIMARY 14 NULL 7 Using where
1 SIMPLE t1 index NULL PRIMARY 14 NULL 15 Using index; Using join buffer
drop table t1, t2;
create table t1 (a char);
insert into t1 values ('a'),('b');
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` VARCHAR(1) COLLATE utf8_general_ci DEFAULT NULL
) ENGINE=DEFAULT COLLATE = utf8_general_ci
create table t2 select max(a),min(a) from t1;
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`max(a)` VARCHAR(1) COLLATE utf8_general_ci DEFAULT NULL,
`min(a)` VARCHAR(1) COLLATE utf8_general_ci DEFAULT NULL
) ENGINE=DEFAULT COLLATE = utf8_general_ci
drop table t2;
create table t2 select concat(a) from t1;
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`concat(a)` VARCHAR(1) COLLATE utf8_general_ci DEFAULT NULL
) ENGINE=DEFAULT COLLATE = utf8_general_ci
drop table t2,t1;
create table t1 (a int);
insert into t1 values (1);
select max(a) as b from t1 having b=1;
b
1
select a from t1 having a=1;
a
1
drop table t1;
create table t1 (a int);
select variance(2) from t1;
variance(2)
NULL
select stddev(2) from t1;
stddev(2)
NULL
drop table t1;
create table t1 (a int);
insert into t1 values (1),(2);
SELECT COUNT(*) FROM t1;
COUNT(*)
2
SELECT COUNT(*) FROM t1;
COUNT(*)
2
SELECT COUNT(*) FROM t1;
COUNT(*)
2
drop table t1;
create table t1 (a int, primary key(a));
insert into t1 values (1),(2);
SELECT max(a) FROM t1;
max(a)
2
SELECT max(a) FROM t1;
max(a)
2
SELECT max(a) FROM t1;
max(a)
2
drop table t1;
CREATE TABLE t1 (a int primary key);
INSERT INTO t1 VALUES (1),(2),(3),(4);
SELECT MAX(a) FROM t1 WHERE a > 5;
MAX(a)
NULL
SELECT MIN(a) FROM t1 WHERE a < 0;
MIN(a)
NULL
DROP TABLE t1;
CREATE TEMPORARY TABLE t1 (
id int NOT NULL auto_increment,
val enum('one','two','three') NOT NULL default 'one',
PRIMARY KEY (id)
) ENGINE=MyISAM;
INSERT INTO t1 VALUES
(1,'one'),(2,'two'),(3,'three'),(4,'one'),(5,'two');
select val, count(*) from t1 group by val;
val count(*)
one 2
two 2
three 1
drop table t1;
create table t1(a int, b datetime);
insert into t1 values (1, NOW()), (2, NOW());
create table t2 select MAX(b) from t1 group by a;
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`MAX(b)` DATETIME DEFAULT NULL
) ENGINE=DEFAULT COLLATE = utf8_general_ci
drop table t1, t2;
create table t1(f1 datetime);
insert into t1 values (now());
create table t2 select f2 from (select max(now()) f2 from t1) a;
show columns from t2;
Field Type Null Default Default_is_NULL On_Update
f2 DATETIME YES YES
drop table t2;
create table t2 select f2 from (select now() f2 from t1) a;
show columns from t2;
Field Type Null Default Default_is_NULL On_Update
f2 DATETIME YES YES
drop table t2, t1;
CREATE TABLE t1(
id int PRIMARY KEY,
a int,
b int,
INDEX i_b_id(a,b,id),
INDEX i_id(a,id)
);
INSERT INTO t1 VALUES
(1,1,4), (2,2,1), (3,1,3), (4,2,1), (5,1,1);
SELECT MAX(id) FROM t1 WHERE id < 3 AND a=2 AND b=6;
MAX(id)
NULL
DROP TABLE t1;
CREATE TABLE t1(
id int PRIMARY KEY,
a int,
b int,
INDEX i_id(a,id),
INDEX i_b_id(a,b,id)
);
INSERT INTO t1 VALUES
(1,1,4), (2,2,1), (3,1,3), (4,2,1), (5,1,1);
SELECT MAX(id) FROM t1 WHERE id < 3 AND a=2 AND b=6;
MAX(id)
NULL
DROP TABLE t1;
CREATE TABLE t1 (id int PRIMARY KEY, b char(3), INDEX(b));
INSERT INTO t1 VALUES (1,'xx'), (2,'aa');
SELECT * FROM t1;
id b
1 xx
2 aa
SELECT MAX(b) FROM t1 WHERE b < 'ppppp';
MAX(b)
aa
SHOW WARNINGS;
Level Code Message
SELECT MAX(b) FROM t1 WHERE b < 'pp';
MAX(b)
aa
DROP TABLE t1;
CREATE TABLE t1 (id int PRIMARY KEY, b char(16), INDEX(b(4)));
INSERT INTO t1 VALUES (1, 'xxxxbbbb'), (2, 'xxxxaaaa');
SELECT MAX(b) FROM t1;
MAX(b)
xxxxbbbb
EXPLAIN SELECT MAX(b) FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
DROP TABLE t1;
CREATE TABLE t1 (a INT, b INT);
INSERT INTO t1 VALUES (1,1),(1,2),(2,3);
SELECT (SELECT COUNT(DISTINCT t1.b)) FROM t1 GROUP BY t1.a;
(SELECT COUNT(DISTINCT t1.b))
2
1
SELECT (SELECT COUNT(DISTINCT 12)) FROM t1 GROUP BY t1.a;
(SELECT COUNT(DISTINCT 12))
1
1
SELECT AVG(2), COUNT(*), COUNT(12),
COUNT(DISTINCT 12), MIN(2),MAX(2),STD(2), VARIANCE(2),SUM(2),
GROUP_CONCAT(2),GROUP_CONCAT(DISTINCT 2);
AVG(2) COUNT(*) COUNT(12) COUNT(DISTINCT 12) MIN(2) MAX(2) STD(2) VARIANCE(2) SUM(2) GROUP_CONCAT(2) GROUP_CONCAT(DISTINCT 2)
2.00000 1 1 1 2 2 0.00000 0.00000 2 2 2
DROP TABLE t1;
create table t2 (ff double);
insert into t2 values (2.2);
select cast(sum(distinct ff) as decimal(5,2)) from t2;
cast(sum(distinct ff) as decimal(5,2))
2.20
select sum(distinct ff) from t2;
sum(distinct ff)
2.2
select cast(variance(ff) as decimal(10,3)) from t2;
cast(variance(ff) as decimal(10,3))
0.000
select cast(min(ff) as decimal(5,2)) from t2;
cast(min(ff) as decimal(5,2))
2.20
create table t1 (df decimal(5,1));
insert into t1 values(1.1);
insert into t1 values(2.2);
select sum(distinct df) from t1;
sum(distinct df)
3.3
select min(df) from t1;
min(df)
1.1
select 1e8 * sum(distinct df) from t1;
1e8 * sum(distinct df)
330000000
select 1e8 * min(df) from t1;
1e8 * min(df)
110000000
create table t3 (ifl int);
insert into t3 values(1), (2);
select cast(min(ifl) as decimal(5,2)) from t3;
cast(min(ifl) as decimal(5,2))
1.00
drop table t1, t2, t3;
CREATE TABLE t1 (id int,value1 float(10,2));
INSERT INTO t1 VALUES (1,0.00),(1,1.00), (1,2.00), (2,10.00), (2,11.00), (2,12.00), (2,13.00);
select id, stddev_pop(value1), var_pop(value1), stddev_samp(value1), var_samp(value1) from t1 group by id;
id stddev_pop(value1) var_pop(value1) stddev_samp(value1) var_samp(value1)
1 0.816497 0.666667 1.000000 1.000000
2 1.118034 1.250000 1.290994 1.666667
DROP TABLE t1;
CREATE TABLE t1 (col1 decimal(16,12));
INSERT INTO t1 VALUES (-5.00000000001),(-5.00000000002),(-5.00000000003),(-5.00000000000),(-5.00000000001),(-5.00000000002);
insert into t1 select * from t1;
select col1,count(col1),sum(col1),avg(col1) from t1 group by col1;
col1 count(col1) sum(col1) avg(col1)
-5.000000000030 2 -10.000000000060 -5.00000000003000000
-5.000000000020 4 -20.000000000080 -5.00000000002000000
-5.000000000010 4 -20.000000000040 -5.00000000001000000
-5.000000000000 2 -10.000000000000 -5.00000000000000000
DROP TABLE t1;
create table t1 (col1 decimal(16,12));
insert into t1 values (-5.00000000001);
insert into t1 values (-5.00000000001);
select col1,sum(col1),max(col1),min(col1) from t1 group by col1;
col1 sum(col1) max(col1) min(col1)
-5.000000000010 -10.000000000020 -5.000000000010 -5.000000000010
delete from t1;
insert into t1 values (5.00000000001);
insert into t1 values (5.00000000001);
select col1,sum(col1),max(col1),min(col1) from t1 group by col1;
col1 sum(col1) max(col1) min(col1)
5.000000000010 10.000000000020 5.000000000010 5.000000000010
DROP TABLE t1;
CREATE TABLE t1 (a VARCHAR(400));
INSERT INTO t1 (a) VALUES ("A"), ("a"), ("a "), ("a "),
("B"), ("b"), ("b "), ("b ");
SELECT COUNT(DISTINCT a) FROM t1;
COUNT(DISTINCT a)
2
DROP TABLE t1;
CREATE TABLE t1 (a int, b int, c int);
INSERT INTO t1 (a, b, c) VALUES
(1,1,1), (1,1,2), (1,1,3),
(1,2,1), (1,2,2), (1,2,3),
(1,3,1), (1,3,2), (1,3,3),
(2,1,1), (2,1,2), (2,1,3),
(2,2,1), (2,2,2), (2,2,3),
(2,3,1), (2,3,2), (2,3,3),
(3,1,1), (3,1,2), (3,1,3),
(3,2,1), (3,2,2), (3,2,3),
(3,3,1), (3,3,2), (3,3,3);
SELECT b/c as v, a FROM t1 ORDER BY v;
v a
0.33333 1
0.33333 2
0.33333 3
0.50000 1
0.50000 2
0.50000 3
0.66667 1
0.66667 2
0.66667 3
1.00000 1
1.00000 1
1.00000 1
1.00000 2
1.00000 2
1.00000 2
1.00000 3
1.00000 3
1.00000 3
1.50000 1
1.50000 2
1.50000 3
2.00000 1
2.00000 2
2.00000 3
3.00000 1
3.00000 2
3.00000 3
SELECT b/c as v, SUM(a) FROM t1 GROUP BY v;
v SUM(a)
0.50000 6
1.00000 18
1.50000 6
2.00000 6
3.00000 6
9999999999.99999 12
SELECT SUM(a) FROM t1 GROUP BY b/c;
SUM(a)
6
18
6
6
6
12
DROP TABLE t1;
set div_precision_increment= @sav_dpi;
CREATE TABLE t1 (a INT PRIMARY KEY, b INT);
INSERT INTO t1 VALUES (1,1), (2,2);
CREATE TABLE t2 (a INT PRIMARY KEY, b INT);
INSERT INTO t2 VALUES (1,1), (3,3);
SELECT
(SELECT SUM(c.a) FROM t1 ttt, t2 ccc
WHERE ttt.a = ccc.b AND ttt.a = t.a GROUP BY ttt.a) AS minid
FROM t1 t, t2 c WHERE t.a = c.b;
minid
NULL
DROP TABLE t1,t2;
create table t1 select variance(0);
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`variance(0)` DOUBLE(8,4) DEFAULT NULL
) ENGINE=DEFAULT COLLATE = utf8_general_ci
drop table t1;
create table t1 select stddev(0);
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`stddev(0)` DOUBLE(8,4) DEFAULT NULL
) ENGINE=DEFAULT COLLATE = utf8_general_ci
drop table t1;
create table bug22555 (i int primary key auto_increment, s1 int, s2 int, e decimal(30,10), o double);
insert into bug22555 (s1, s2, e, o) values (53, 78, 11.4276528, 6.828112), (17, 78, 5.916793, 1.8502951), (18, 76, 2.679231, 9.17975591), (31, 62, 6.07831, 0.1), (19, 41, 5.37463, 15.1), (83, 73, 14.567426, 7.959222), (92, 53, 6.10151, 13.1856852), (7, 12, 13.92272, 3.442007), (92, 35, 11.95358909, 6.01376678), (38, 84, 2.572, 7.904571);
select std(s1/s2) from bug22555 group by i;
std(s1/s2)
0.00000000
0.00000000
0.00000000
0.00000000
0.00000000
0.00000000
0.00000000
0.00000000
0.00000000
0.00000000
select std(e) from bug22555 group by i;
std(e)
0.00000000000000
0.00000000000000
0.00000000000000
0.00000000000000
0.00000000000000
0.00000000000000
0.00000000000000
0.00000000000000
0.00000000000000
0.00000000000000
select std(o) from bug22555 group by i;
std(o)
0
0
0
0
0
0
0
0
0
0
drop table bug22555;
create table bug22555 (i int, s1 int, s2 int, o1 double, o2 double, e1 decimal, e2 decimal);
insert into bug22555 values (1,53,78,53,78,53,78),(2,17,78,17,78,17,78),(3,18,76,18,76,18,76);
select i, count(*) from bug22555 group by i;
i count(*)
1 1
2 1
3 1
select std(s1/s2) from bug22555 where i=1;
std(s1/s2)
0.00000000
select std(s1/s2) from bug22555 where i=2;
std(s1/s2)
0.00000000
select std(s1/s2) from bug22555 where i=3;
std(s1/s2)
0.00000000
select std(s1/s2) from bug22555 where i=1 group by i;
std(s1/s2)
0.00000000
select std(s1/s2) from bug22555 where i=2 group by i;
std(s1/s2)
0.00000000
select std(s1/s2) from bug22555 where i=3 group by i;
std(s1/s2)
0.00000000
select std(s1/s2) from bug22555 group by i order by i;
std(s1/s2)
0.00000000
0.00000000
0.00000000
select i, count(*), std(o1/o2) from bug22555 group by i order by i;
i count(*) std(o1/o2)
1 1 0
2 1 0
3 1 0
select i, count(*), std(e1/e2) from bug22555 group by i order by i;
i count(*) std(e1/e2)
1 1 0.00000000
2 1 0.00000000
3 1 0.00000000
set @saved_div_precision_increment=@@div_precision_increment;
set div_precision_increment=19;
select i, count(*), variance(s1/s2) from bug22555 group by i order by i;
i count(*) variance(s1/s2)
1 1 0.000000000000000000000000000000
2 1 0.000000000000000000000000000000
3 1 0.000000000000000000000000000000
select i, count(*), variance(o1/o2) from bug22555 group by i order by i;
i count(*) variance(o1/o2)
1 1 0
2 1 0
3 1 0
select i, count(*), variance(e1/e2) from bug22555 group by i order by i;
i count(*) variance(e1/e2)
1 1 0.000000000000000000000000000000
2 1 0.000000000000000000000000000000
3 1 0.000000000000000000000000000000
select i, count(*), std(s1/s2) from bug22555 group by i order by i;
i count(*) std(s1/s2)
1 1 0.000000000000000000000000000000
2 1 0.000000000000000000000000000000
3 1 0.000000000000000000000000000000
select i, count(*), std(o1/o2) from bug22555 group by i order by i;
i count(*) std(o1/o2)
1 1 0
2 1 0
3 1 0
select i, count(*), std(e1/e2) from bug22555 group by i order by i;
i count(*) std(e1/e2)
1 1 0.000000000000000000000000000000
2 1 0.000000000000000000000000000000
3 1 0.000000000000000000000000000000
set div_precision_increment=20;
select i, count(*), variance(s1/s2) from bug22555 group by i order by i;
i count(*) variance(s1/s2)
1 1 0.000000000000000000000000000000
2 1 0.000000000000000000000000000000
3 1 0.000000000000000000000000000000
select i, count(*), variance(o1/o2) from bug22555 group by i order by i;
i count(*) variance(o1/o2)
1 1 0
2 1 0
3 1 0
select i, count(*), variance(e1/e2) from bug22555 group by i order by i;
i count(*) variance(e1/e2)
1 1 0.000000000000000000000000000000
2 1 0.000000000000000000000000000000
3 1 0.000000000000000000000000000000
select i, count(*), std(s1/s2) from bug22555 group by i order by i;
i count(*) std(s1/s2)
1 1 0.000000000000000000000000000000
2 1 0.000000000000000000000000000000
3 1 0.000000000000000000000000000000
select i, count(*), std(o1/o2) from bug22555 group by i order by i;
i count(*) std(o1/o2)
1 1 0
2 1 0
3 1 0
select i, count(*), std(e1/e2) from bug22555 group by i order by i;
i count(*) std(e1/e2)
1 1 0.000000000000000000000000000000
2 1 0.000000000000000000000000000000
3 1 0.000000000000000000000000000000
set @@div_precision_increment=@saved_div_precision_increment;
insert into bug22555 values (1,53,78,53,78,53,78),(2,17,78,17,78,17,78),(3,18,76,18,76,18,76);
insert into bug22555 values (1,53,78,53,78,53,78),(2,17,78,17,78,17,78),(3,18,76,18,76,18,76);
insert into bug22555 values (1,53,78,53,78,53,78),(2,17,78,17,78,17,78),(3,18,76,18,76,18,76);
select i, count(*), std(s1/s2) from bug22555 group by i order by i;
i count(*) std(s1/s2)
1 4 0.00000000
2 4 0.00000000
3 4 0.00000000
select i, count(*), round(std(o1/o2), 16) from bug22555 group by i order by i;
i count(*) round(std(o1/o2), 16)
1 4 0.0000000000000000
2 4 0.0000000000000000
3 4 0.0000000000000000
select i, count(*), std(e1/e2) from bug22555 group by i order by i;
i count(*) std(e1/e2)
1 4 0.00000000
2 4 0.00000000
3 4 0.00000000
select std(s1/s2) from bug22555;
std(s1/s2)
0.21325764
select std(o1/o2) from bug22555;
std(o1/o2)
0.213257635866493
select std(e1/e2) from bug22555;
std(e1/e2)
0.21325764
set @saved_div_precision_increment=@@div_precision_increment;
set div_precision_increment=19;
select i, count(*), std(s1/s2) from bug22555 group by i order by i;
i count(*) std(s1/s2)
1 4 0.000000000000000000000000000000
2 4 0.000000000000000000000000000000
3 4 0.000000000000000000000000000000
select i, count(*), round(std(o1/o2), 16) from bug22555 group by i order by i;
i count(*) round(std(o1/o2), 16)
1 4 0.0000000000000000
2 4 0.0000000000000000
3 4 0.0000000000000000
select i, count(*), std(e1/e2) from bug22555 group by i order by i;
i count(*) std(e1/e2)
1 4 0.000000000000000000000000000000
2 4 0.000000000000000000000000000000
3 4 0.000000000000000000000000000000
select round(std(s1/s2), 17) from bug22555;
round(std(s1/s2), 17)
0.21325763586649340
select std(o1/o2) from bug22555;
std(o1/o2)
0.213257635866493
select round(std(e1/e2), 17) from bug22555;
round(std(e1/e2), 17)
0.21325763586649340
set div_precision_increment=20;
select i, count(*), std(s1/s2) from bug22555 group by i order by i;
i count(*) std(s1/s2)
1 4 0.000000000000000000000000000000
2 4 0.000000000000000000000000000000
3 4 0.000000000000000000000000000000
select i, count(*), round(std(o1/o2), 16) from bug22555 group by i order by i;
i count(*) round(std(o1/o2), 16)
1 4 0.0000000000000000
2 4 0.0000000000000000
3 4 0.0000000000000000
select i, count(*), std(e1/e2) from bug22555 group by i order by i;
i count(*) std(e1/e2)
1 4 0.000000000000000000000000000000
2 4 0.000000000000000000000000000000
3 4 0.000000000000000000000000000000
select round(std(s1/s2), 17) from bug22555;
round(std(s1/s2), 17)
0.21325763586649340
select std(o1/o2) from bug22555;
std(o1/o2)
0.213257635866493
select round(std(e1/e2), 17) from bug22555;
round(std(e1/e2), 17)
0.21325763586649340
set @@div_precision_increment=@saved_div_precision_increment;
drop table bug22555;
create table bug22555 (s int, o double, e decimal);
insert into bug22555 values (1,1,1),(2,2,2),(3,3,3),(6,6,6),(7,7,7);
select var_samp(s), var_pop(s) from bug22555;
var_samp(s) var_pop(s)
6.7000 5.3600
select var_samp(o), var_pop(o) from bug22555;
var_samp(o) var_pop(o)
6.7 5.36
select var_samp(e), var_pop(e) from bug22555;
var_samp(e) var_pop(e)
6.7000 5.3600
drop table bug22555;
create table bug22555 (s int, o double, e decimal);
insert into bug22555 values (null,null,null),(null,null,null);
select var_samp(s) as 'null', var_pop(s) as 'null' from bug22555;
null null
NULL NULL
select var_samp(o) as 'null', var_pop(o) as 'null' from bug22555;
null null
NULL NULL
select var_samp(e) as 'null', var_pop(e) as 'null' from bug22555;
null null
NULL NULL
insert into bug22555 values (1,1,1);
select var_samp(s) as 'null', var_pop(s) as '0' from bug22555;
null 0
NULL 0.0000
select var_samp(o) as 'null', var_pop(o) as '0' from bug22555;
null 0
NULL 0
select var_samp(e) as 'null', var_pop(e) as '0' from bug22555;
null 0
NULL 0.0000
insert into bug22555 values (2,2,2);
select var_samp(s) as '0.5', var_pop(s) as '0.25' from bug22555;
0.5 0.25
0.5000 0.2500
select var_samp(o) as '0.5', var_pop(o) as '0.25' from bug22555;
0.5 0.25
0.5 0.25
select var_samp(e) as '0.5', var_pop(e) as '0.25' from bug22555;
0.5 0.25
0.5000 0.2500
drop table bug22555;
create table t1 (a decimal(20));
insert into t1 values (12345678901234567890);
select count(a) from t1;
count(a)
1
select count(distinct a) from t1;
count(distinct a)
1
drop table t1;
CREATE TABLE t1 (a INT, b INT);
INSERT INTO t1 VALUES (1,1),(1,2),(1,3),(1,4),(1,5),(1,6),(1,7),(1,8);
INSERT INTO t1 SELECT a, b+8 FROM t1;
INSERT INTO t1 SELECT a, b+16 FROM t1;
INSERT INTO t1 SELECT a, b+32 FROM t1;
INSERT INTO t1 SELECT a, b+64 FROM t1;
INSERT INTO t1 SELECT a, b+128 FROM t1;
INSERT INTO t1 SELECT a, b+256 FROM t1;
INSERT INTO t1 SELECT a, b+512 FROM t1;
INSERT INTO t1 SELECT a, b+1024 FROM t1;
INSERT INTO t1 SELECT a, b+2048 FROM t1;
INSERT INTO t1 SELECT a, b+4096 FROM t1;
INSERT INTO t1 SELECT a, b+8192 FROM t1;
INSERT INTO t1 SELECT a, b+16384 FROM t1;
INSERT INTO t1 SELECT a, b+32768 FROM t1;
SELECT a,COUNT(DISTINCT b) AS cnt FROM t1 GROUP BY a HAVING cnt > 50;
a cnt
1 65536
SELECT a,SUM(DISTINCT b) AS sumation FROM t1 GROUP BY a HAVING sumation > 50;
a sumation
1 2147516416
SELECT a,AVG(DISTINCT b) AS average FROM t1 GROUP BY a HAVING average > 50;
a average
1 32768.5000
DROP TABLE t1;
CREATE TABLE t1 ( a INT, b INT, KEY(a) );
INSERT INTO t1 VALUES (NULL, 1), (NULL, 2);
EXPLAIN SELECT MIN(a), MIN(b) FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
SELECT MIN(a), MIN(b) FROM t1;
MIN(a) MIN(b)
NULL 1
CREATE TABLE t2( a INT, b INT, c INT, KEY(a, b) );
INSERT INTO t2 ( a, b, c ) VALUES ( 1, NULL, 2 ), ( 1, 3, 4 ), ( 1, 4, 4 );
EXPLAIN SELECT MIN(b), MIN(c) FROM t2 WHERE a = 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref a a 5 const 1 Using where
SELECT MIN(b), MIN(c) FROM t2 WHERE a = 1;
MIN(b) MIN(c)
3 2
CREATE TABLE t3 (a INT, b INT, c int, KEY(a, b));
INSERT INTO t3 VALUES (1, NULL, 1), (2, NULL, 2), (2, NULL, 2), (3, NULL, 3);
EXPLAIN SELECT MIN(a), MIN(b) FROM t3 where a = 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
SELECT MIN(a), MIN(b) FROM t3 where a = 2;
MIN(a) MIN(b)
2 NULL
CREATE TABLE t4 (a INT, b INT, c int, KEY(a, b));
INSERT INTO t4 VALUES (1, 1, 1), (2, NULL, 2), (2, NULL, 2), (3, 1, 3);
EXPLAIN SELECT MIN(a), MIN(b) FROM t4 where a = 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
SELECT MIN(a), MIN(b) FROM t4 where a = 2;
MIN(a) MIN(b)
2 NULL
SELECT MIN(b), min(c) FROM t4 where a = 2;
MIN(b) min(c)
NULL 2
CREATE TABLE t5( a INT, b INT, KEY( a, b) );
INSERT INTO t5 VALUES( 1, 1 ), ( 1, 2 );
EXPLAIN SELECT MIN(a), MIN(b) FROM t5 WHERE a = 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
SELECT MIN(a), MIN(b) FROM t5 WHERE a = 1;
MIN(a) MIN(b)
1 1
SELECT MIN(a), MIN(b) FROM t5 WHERE a = 1 and b > 1;
MIN(a) MIN(b)
1 2
DROP TABLE t1, t2, t3, t4, t5;
CREATE TABLE t1 (a int, b date NOT NULL, KEY k1 (a,b));
SELECT MIN(b) FROM t1 WHERE a=1 AND b>'2007-08-01';
MIN(b)
NULL
DROP TABLE t1;
CREATE TABLE t1(a DOUBLE);
INSERT INTO t1 VALUES (10), (20);
SELECT AVG(a), CAST(AVG(a) AS DECIMAL) FROM t1;
AVG(a) CAST(AVG(a) AS DECIMAL)
15 15
DROP TABLE t1;
End of 5.0 tests
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