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mariadb/mysql-test/r/func_group.result
unknown 8e7217e43b Fix for BUG#12882 - min/max inconsistent on empty table. 
The problem was in that the MIN/MAX optimization in opt_sum_query was
replacing MIN/MAX functions with their constant argument without
taking into account that a query has no result rows.


mysql-test/r/func_group.result:
  Test for BUG#12882.
mysql-test/t/func_group.test:
  Test for BUG#12882.
sql/item_sum.cc:
  If it is known that a query has no result rows, do not call add()
  via the call to Item_sum::no_rows_in_result() which calls reset().
  Instead directly call clear() so that the MIN and MAX functions
  produce NULL when there are no result rows.
sql/opt_sum.cc:
  * Do not apply MIN/MAX optimization when the operand of MIN/MAX is
    a constant if it can't be determined whether the query has any
    result rows. The reason is that if the query has result rows,
    then the result of MIN/MAX is its constant argument, but if the
    query result is empty, then the result of MIN/MAX must be NULL
    irrespective of its argument.
  
  * The patch also simplifies a bit the branch that hadles COUNT().
2005-09-21 09:49:19 +03:00

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drop table if exists t1,t2;
create table t1 (grp int, a bigint unsigned, 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
select sum(all a),count(all a),avg(all a),std(all a),variance(all a),bit_or(all a),bit_and(all a),min(all a),max(all a),min(all c),max(all c) from t1;
sum(all a) count(all a) avg(all a) std(all a) variance(all a) bit_or(all a) bit_and(all a) min(all a) max(all a) min(all c) max(all c)
21 6 3.5000 1.7078 2.9167 7 0 1 6 E
select grp, sum(a),count(a),avg(a),std(a),variance(a),bit_or(a),bit_and(a),min(a),max(a),min(c),max(c) from t1 group by grp;
grp sum(a) count(a) avg(a) std(a) variance(a) bit_or(a) bit_and(a) min(a) max(a) min(c) max(c)
NULL NULL 0 NULL NULL NULL 0 18446744073709551615 NULL NULL
1 1 1 1.0000 0.0000 0.0000 1 1 1 1 a a
2 5 2 2.5000 0.5000 0.2500 3 2 2 3 b c
3 15 3 5.0000 0.8165 0.6667 7 4 4 6 C E
select grp, sum(a)+count(a)+avg(a)+std(a)+variance(a)+bit_or(a)+bit_and(a)+min(a)+max(a)+min(c)+max(c) as sum from t1 group by grp;
grp sum
NULL NULL
1 7
2 20.25
3 45.483163247594
create table t2 (grp int, a bigint unsigned, 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(11),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(11),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 1.000000 0.816497 0.666667
2 11.000000 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 1.000000 0.816497 0.666667
Set Two 11.000000 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 3.0000
2 NULL
3 2.0000
drop table t1,t2;
create table t1 (a smallint(6) 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 aaa AAA 10
10 NULL AAA 10
10 bbb AAA 10
20 zzz AAA 10
10 aaa BBB 20
10 NULL BBB 20
10 bbb BBB 20
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, b int);
select count(b), sum(b), avg(b), std(b), min(b), max(b), bit_and(b), bit_or(b) from t1;
count(b) sum(b) avg(b) std(b) min(b) max(b) bit_and(b) bit_or(b)
0 NULL NULL NULL NULL NULL 18446744073709551615 0
select a,count(b), sum(b), avg(b), std(b), min(b), max(b), bit_and(b), bit_or(b) from t1 group by a;
a count(b) sum(b) avg(b) std(b) min(b) max(b) bit_and(b) bit_or(b)
insert into t1 values (1,null);
select a,count(b), sum(b), avg(b), std(b), min(b), max(b), bit_and(b), bit_or(b) from t1 group by a;
a count(b) sum(b) avg(b) std(b) min(b) max(b) bit_and(b) bit_or(b)
1 0 NULL NULL NULL NULL NULL 18446744073709551615 0
insert into t1 values (1,null);
insert into t1 values (2,null);
select a,count(b), sum(b), avg(b), std(b), min(b), max(b), bit_and(b), bit_or(b) from t1 group by a;
a count(b) sum(b) avg(b) std(b) min(b) max(b) bit_and(b) bit_or(b)
1 0 NULL NULL NULL NULL NULL 18446744073709551615 0
2 0 NULL NULL NULL NULL NULL 18446744073709551615 0
select SQL_BIG_RESULT a,count(b), sum(b), avg(b), std(b), min(b), max(b), bit_and(b), bit_or(b) from t1 group by a;
a count(b) sum(b) avg(b) std(b) min(b) max(b) bit_and(b) bit_or(b)
1 0 NULL NULL NULL NULL NULL 18446744073709551615 0
2 0 NULL NULL NULL NULL NULL 18446744073709551615 0
insert into t1 values (2,1);
select a,count(b), sum(b), avg(b), std(b), min(b), max(b), bit_and(b), bit_or(b) from t1 group by a;
a count(b) sum(b) avg(b) std(b) min(b) max(b) bit_and(b) bit_or(b)
1 0 NULL NULL NULL NULL NULL 18446744073709551615 0
2 1 1 1.0000 0.0000 1 1 1 1
select SQL_BIG_RESULT a,count(b), sum(b), avg(b), std(b), min(b), max(b), bit_and(b), bit_or(b) from t1 group by a;
a count(b) sum(b) avg(b) std(b) min(b) max(b) bit_and(b) bit_or(b)
1 0 NULL NULL NULL NULL NULL 18446744073709551615 0
2 1 1 1.0000 0.0000 1 1 1 1
insert into t1 values (3,1);
select a,count(b), sum(b), avg(b), std(b), min(b), max(b), bit_and(b), bit_or(b) from t1 group by a;
a count(b) sum(b) avg(b) std(b) min(b) max(b) bit_and(b) bit_or(b)
1 0 NULL NULL NULL NULL NULL 18446744073709551615 0
2 1 1 1.0000 0.0000 1 1 1 1
3 1 1 1.0000 0.0000 1 1 1 1
select SQL_BIG_RESULT a,count(b), sum(b), avg(b), std(b), min(b), max(b), bit_and(b), bit_or(b), bit_xor(b) from t1 group by a;
a count(b) sum(b) avg(b) std(b) min(b) max(b) bit_and(b) bit_or(b) bit_xor(b)
1 0 NULL NULL NULL NULL NULL 18446744073709551615 0 0
2 1 1 1.0000 0.0000 1 1 1 1 1
3 1 1 1.0000 0.0000 1 1 1 1 1
explain extended select SQL_BIG_RESULT a,count(b), sum(b), avg(b), std(b), min(b), max(b), bit_and(b), bit_or(b), bit_xor(b) from t1 group by a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using filesort
Warnings:
Note 1003 select sql_big_result test.t1.a AS `a`,count(test.t1.b) AS `count(b)`,sum(test.t1.b) AS `sum(b)`,avg(test.t1.b) AS `avg(b)`,std(test.t1.b) AS `std(b)`,min(test.t1.b) AS `min(b)`,max(test.t1.b) AS `max(b)`,bit_and(test.t1.b) AS `bit_and(b)`,bit_or(test.t1.b) AS `bit_or(b)`,bit_xor(test.t1.b) AS `bit_xor(b)` from test.t1 group by test.t1.a
drop table t1;
create table t1 (col int);
insert into t1 values (-1), (-2), (-3);
select bit_and(col), bit_or(col) from t1;
bit_and(col) bit_or(col)
18446744073709551612 18446744073709551615
select SQL_BIG_RESULT bit_and(col), bit_or(col) from t1 group by col;
bit_and(col) bit_or(col)
18446744073709551613 18446744073709551613
18446744073709551614 18446744073709551614
18446744073709551615 18446744073709551615
drop table t1;
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 smallint,
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 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');
select * from t1;
a1 a2 a3 a4 a5
AME 0 SEA 0.1 1942-02-19
HBR 1 SEA 0.085 1948-03-05
BOT 2 SEA 0.085 1951-11-29
BMC 3 SEA 0.085 1958-09-08
TWU 0 LAX 0.08 1969-10-05
BDL 0 DEN 0.08 1960-11-27
DTX 1 NYC 0.08 1961-05-04
PLS 1 WDC 0.075 1949-01-02
ZAJ 2 CHI 0.075 1960-06-15
VVV 2 MIN 0.075 1959-06-28
GTM 3 DAL 0.07 1977-09-23
SSJ NULL CHI NULL 1974-03-19
KKK 3 ATL NULL NULL
XXX NULL MIN NULL NULL
select * from t2;
a1 a2 a3 a4
TKF Seattle WA AME
LCC Los Angeles CA TWU
DEN Denver CO BDL
SDC San Diego CA TWU
NOL New Orleans LA GTM
LAK Los Angeles CA TWU
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 noticed after reading const tables
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 15 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 range PRIMARY PRIMARY 3 NULL 14 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 3 NULL 5 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 7 NULL 1 Using where; Using index
1 SIMPLE t2 range k1 k1 3 NULL 4 Using where; Using index
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 k2 12 NULL 14 Using index
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 k2 12 NULL 14 Using index
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 k1 7 NULL 14 Using where; Using index
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 k1 7 NULL 14 Using where; Using index
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 k1 7 NULL 14 Using where; Using index
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 k1 7 NULL 14 Using where; Using index
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 ALL PRIMARY NULL NULL NULL 14 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 k2 12 NULL 14 Using where; Using index
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 range k2 k2 4 NULL 6 Using where; Using index
1 SIMPLE t1 index NULL PRIMARY 3 NULL 14 Using index
drop table t1, t2;
create table t1 (USR_ID integer not null, MAX_REQ integer not null, constraint PK_SEA_USER primary key (USR_ID)) engine=InnoDB;
insert into t1 values (1, 3);
select count(*) + MAX_REQ - MAX_REQ + MAX_REQ - MAX_REQ + MAX_REQ - MAX_REQ + MAX_REQ - MAX_REQ + MAX_REQ - MAX_REQ from t1 group by MAX_REQ;
count(*) + MAX_REQ - MAX_REQ + MAX_REQ - MAX_REQ + MAX_REQ - MAX_REQ + MAX_REQ - MAX_REQ + MAX_REQ - MAX_REQ
1
select Case When Count(*) < MAX_REQ Then 1 Else 0 End from t1 where t1.USR_ID = 1 group by MAX_REQ;
Case When Count(*) < MAX_REQ Then 1 Else 0 End
1
drop table t1;
create table t1 (a char(10));
insert into t1 values ('a'),('b'),('c');
select coercibility(max(a)) from t1;
coercibility(max(a))
2
drop table t1;
create table t1 (a char character set latin2);
insert into t1 values ('a'),('b');
select charset(max(a)), coercibility(max(a)),
charset(min(a)), coercibility(min(a)) from t1;
charset(max(a)) coercibility(max(a)) charset(min(a)) coercibility(min(a))
latin2 2 latin2 2
create table t2 select max(a),min(a) from t1;
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`max(a)` char(1) character set latin2 default NULL,
`min(a)` char(1) character set latin2 default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
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);
prepare stmt1 from 'SELECT COUNT(*) FROM t1';
execute stmt1;
COUNT(*)
2
execute stmt1;
COUNT(*)
2
execute stmt1;
COUNT(*)
2
deallocate prepare stmt1;
drop table t1;
create table t1 (a int, primary key(a));
insert into t1 values (1),(2);
prepare stmt1 from 'SELECT max(a) FROM t1';
execute stmt1;
max(a)
2
execute stmt1;
max(a)
2
execute stmt1;
max(a)
2
deallocate prepare stmt1;
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 TABLE t1 (
id int(10) unsigned NOT NULL auto_increment,
val enum('one','two','three') NOT NULL default 'one',
PRIMARY KEY (id)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
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 (
id int(10) unsigned NOT NULL auto_increment,
val set('one','two','three') NOT NULL default 'one',
PRIMARY KEY (id)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
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=MyISAM DEFAULT CHARSET=latin1
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 Key Default Extra
f2 datetime YES NULL
drop table t2;
create table t2 select f2 from (select now() f2 from t1) a;
show columns from t2;
Field Type Null Key Default Extra
f2 datetime 0000-00-00 00:00:00
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 t1m (a int) engine=myisam;
create table t1i (a int) engine=innodb;
create table t2m (a int) engine=myisam;
create table t2i (a int) engine=innodb;
insert into t2m values (5);
insert into t2i values (5);
select min(a) from t1m;
min(a)
NULL
select min(7) from t1m;
min(7)
NULL
select min(7) from DUAL;
min(7)
NULL
explain select min(7) from t2m join t1m;
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(7) from t2m join t1m;
min(7)
NULL
select max(a) from t1m;
max(a)
NULL
select max(7) from t1m;
max(7)
NULL
select max(7) from DUAL;
max(7)
NULL
explain select max(7) from t2m join t1m;
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(7) from t2m join t1m;
max(7)
NULL
select 1, min(a) from t1m where a=99;
1 min(a)
1 NULL
select 1, min(a) from t1m where 1=99;
1 min(a)
1 NULL
select 1, min(1) from t1m where a=99;
1 min(1)
select 1, min(1) from t1m where 1=99;
1 min(1)
1 NULL
select 1, max(a) from t1m where a=99;
1 max(a)
1 NULL
select 1, max(a) from t1m where 1=99;
1 max(a)
1 NULL
select 1, max(1) from t1m where a=99;
1 max(1)
select 1, max(1) from t1m where 1=99;
1 max(1)
1 NULL
select min(a) from t1i;
min(a)
NULL
select min(7) from t1i;
min(7)
NULL
select min(7) from DUAL;
min(7)
NULL
explain select min(7) from t2i join t1i;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2i ALL NULL NULL NULL NULL 1
1 SIMPLE t1i ALL NULL NULL NULL NULL 1
select min(7) from t2i join t1i;
min(7)
NULL
select max(a) from t1i;
max(a)
NULL
select max(7) from t1i;
max(7)
NULL
select max(7) from DUAL;
max(7)
NULL
explain select max(7) from t2i join t1i;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2i ALL NULL NULL NULL NULL 1
1 SIMPLE t1i ALL NULL NULL NULL NULL 1
select max(7) from t2i join t1i;
max(7)
NULL
select 1, min(a) from t1i where a=99;
1 min(a)
1 NULL
select 1, min(a) from t1i where 1=99;
1 min(a)
1 NULL
select 1, min(1) from t1i where a=99;
1 min(1)
1 NULL
select 1, min(1) from t1i where 1=99;
1 min(1)
1 NULL
select 1, max(a) from t1i where a=99;
1 max(a)
1 NULL
select 1, max(a) from t1i where 1=99;
1 max(a)
1 NULL
select 1, max(1) from t1i where a=99;
1 max(1)
1 NULL
select 1, max(1) from t1i where 1=99;
1 max(1)
1 NULL
explain select count(*), min(7), max(7) from t1m, t1i;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1m system NULL NULL NULL NULL 0 const row not found
1 SIMPLE t1i ALL NULL NULL NULL NULL 1
select count(*), min(7), max(7) from t1m, t1i;
count(*) min(7) max(7)
0 NULL NULL
explain select count(*), min(7), max(7) from t1m, t2i;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1m system NULL NULL NULL NULL 0 const row not found
1 SIMPLE t2i ALL NULL NULL NULL NULL 1
select count(*), min(7), max(7) from t1m, t2i;
count(*) min(7) max(7)
0 NULL NULL
explain select count(*), min(7), max(7) from t2m, t1i;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2m system NULL NULL NULL NULL 1
1 SIMPLE t1i ALL NULL NULL NULL NULL 1
select count(*), min(7), max(7) from t2m, t1i;
count(*) min(7) max(7)
0 NULL NULL
drop table t1m, t1i, t2m, t2i;
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