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 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 3.50000 1.70783 2.91667 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 1.00000 0.00000 0.00000 1 1 1 1 a a 2 5 2 2.50000 0.50000 0.25000 3 2 2 3 b c 3 15 3 5.00000 0.81650 0.66667 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 1.0000000 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 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 aaa BBB 20 10 NULL AAA 10 10 NULL 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, 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 1.00000 0.00000 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 1.00000 0.00000 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 1.00000 0.00000 1 1 1 1 3 1 1 1.00000 0.00000 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 1.00000 0.00000 1 1 1 1 1 3 1 1 1.00000 0.00000 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 filtered Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 5 100.00 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 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 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 WWW 1 LED 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 AAA AAA AA 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 index PRIMARY PRIMARY 3 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 index PRIMARY PRIMARY 3 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 3 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 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 15 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 15 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 15 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 15 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 15 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 15 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 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 k2 12 NULL 15 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 15 Using index drop table t1, t2; 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 show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `a` char(1) CHARACTER SET latin2 DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 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; create table t2 select concat(a) from t1; show create table t2; Table Create Table t2 CREATE TABLE `t2` ( `concat(a)` varchar(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 NO 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 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 (id int , b varchar(512), INDEX(b(250))) COLLATE latin1_bin; INSERT INTO t1 VALUES (1,CONCAT(REPEAT('_', 250), "qq")), (1,CONCAT(REPEAT('_', 250), "zz")), (1,CONCAT(REPEAT('_', 250), "aa")), (1,CONCAT(REPEAT('_', 250), "ff")); SELECT MAX(b) FROM t1; MAX(b) __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________zz 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 4 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), BIT_AND(2), BIT_OR(2), BIT_XOR(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) BIT_AND(2) BIT_OR(2) BIT_XOR(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 2 2 2 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 cast(sum(distinct ff) as signed) from t2; cast(sum(distinct ff) as signed) 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 cast(sum(distinct df) as signed) from t1; cast(sum(distinct df) as signed) 3 select cast(min(df) as signed) from t1; cast(min(df) as signed) 0 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(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), (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 3 0.33333 1 0.33333 2 0.50000 1 0.50000 2 0.50000 3 0.66667 2 0.66667 1 0.66667 3 1.00000 3 1.00000 2 1.00000 3 1.00000 1 1.00000 2 1.00000 3 1.00000 2 1.00000 1 1.00000 1 1.50000 3 1.50000 2 1.50000 1 2.00000 1 2.00000 3 2.00000 2 3.00000 3 3.00000 2 3.00000 1 SELECT b/c as v, SUM(a) FROM t1 GROUP BY v; v SUM(a) 0.33333 6 0.50000 6 0.66667 6 1.00000 18 1.50000 6 2.00000 6 3.00000 6 SELECT SUM(a) FROM t1 GROUP BY b/c; SUM(a) 6 6 6 18 6 6 6 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 SQL_NO_CACHE (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 1 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=MyISAM DEFAULT CHARSET=latin1 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=MyISAM DEFAULT CHARSET=latin1 drop table t1; create table bug22555 (i smallint primary key auto_increment, s1 smallint, s2 smallint, 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 smallint, s1 smallint, s2 smallint, 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) 0.21325763586649 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) 0.21325763586649341 select std(o1/o2) from bug22555; std(o1/o2) 0.21325763586649 select round(std(e1/e2), 17) from bug22555; round(std(e1/e2), 17) 0.21325763586649341 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) 0.21325763586649341 select std(o1/o2) from bug22555; std(o1/o2) 0.21325763586649 select round(std(e1/e2), 17) from bug22555; round(std(e1/e2), 17) 0.21325763586649341 set @@div_precision_increment=@saved_div_precision_increment; drop table bug22555; create table bug22555 (s smallint, 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 smallint, 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 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; End of 5.0 tests