A B C
SH001 001 2008-12-23 00:00:00.000
SH001 001 2008-12-24 00:00:00.000
SH001 001 2008-12-25 00:00:00.000
SH001 002 2008-12-23 00:00:00.000
SH001 002 2008-12-25 00:00:00.000
SH001 aa 2008-12-25 00:00:00.000
A B C
SH001 001 2008-12-23 00:00:00.000
SH001 002 2008-12-23 00:00:00.000
SH001 aa 2008-12-25 00:00:00.000要求:SQL2000,不能用临时表,必须一条SQL语句完成。谢谢各位大侠
SH001 001 2008-12-23 00:00:00.000
SH001 001 2008-12-24 00:00:00.000
SH001 001 2008-12-25 00:00:00.000
SH001 002 2008-12-23 00:00:00.000
SH001 002 2008-12-25 00:00:00.000
SH001 aa 2008-12-25 00:00:00.000
A B C
SH001 001 2008-12-23 00:00:00.000
SH001 002 2008-12-23 00:00:00.000
SH001 aa 2008-12-25 00:00:00.000要求:SQL2000,不能用临时表,必须一条SQL语句完成。谢谢各位大侠
INSERT @TB
SELECT 'SH001', '001', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-24 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', 'aa', '2008-12-25 00:00:00.000'
SELECT * FROM @TB AS A WHERE NOT EXISTS(SELECT 1 FROM @TB WHERE A=A.A AND B=A.B AND C<A.C)
/*
A B C
----- ---- ------------------------------------------------------
SH001 001 2008-12-23 00:00:00.000
SH001 002 2008-12-23 00:00:00.000
SH001 aa 2008-12-25 00:00:00.000
*/
INSERT @TB
SELECT 'SH001', '001', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-24 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', 'aa', '2008-12-25 00:00:00.000'select A, B, C=min(C)
from @TB
group by A,B/*
A B C
----- ---- -----------------------
SH001 001 2008-12-23 00:00:00.000
SH001 002 2008-12-23 00:00:00.000
SH001 aa 2008-12-25 00:00:00.000(3 行受影响)*/
INSERT @TB
SELECT 'SH001', '001', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-24 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', 'aa', '2008-12-25 00:00:00.000'
select A,B,MIN(C) C FROM @TB GROUP BY A,B
A B C
----- ---- ------------------------------------------------------
SH001 001 2008-12-23 00:00:00.000
SH001 002 2008-12-23 00:00:00.000
SH001 aa 2008-12-25 00:00:00.000(所影响的行数为 3 行)
(
A varchar(10),
B varchar(5),
C datetime
)insert into test SELECT 'SH001', '001', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-24 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', 'aa', '2008-12-25 00:00:00.000'
select * from testselect a,b,c=min(c) from test group by a,b
INSERT @TB
SELECT 'SH001', '001', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-24 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', 'aa', '2008-12-25 00:00:00.000'select a,b,min(c) from @tb group by b,a
INSERT tb
SELECT 'SH001', '001', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-24 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', 'aa', '2008-12-25 00:00:00.000'
go--方法1:
select a.* from tb a where C = (select min(C) from tb where A = a.A and B = a.B) order by a.A , a.B
--方法2:
select a.* from tb a where not exists(select 1 from tb where A = a.A and B = a.B and C < a.C) order by a.A , a.B
--方法3:
select a.* from tb a,(select A,B,min(C) C from tb group by A , B) b where a.A = b.A and a.B = b.B and a.C = b.C order by a.A , a.Bdrop table tb/*
A B C
----- ---- ------------------------------------------------------
SH001 001 2008-12-23 00:00:00.000
SH001 002 2008-12-23 00:00:00.000
SH001 aa 2008-12-25 00:00:00.000(所影响的行数为 3 行)
*/--更多方法和说明见下:--按某一字段分组取最大(小)值所在行的数据
--(爱新觉罗.毓华(十八年风雨,守得冰山雪莲花开) 2007-10-23于浙江杭州)
/*
数据如下:
name val memo
a 2 a2(a的第二个值)
a 1 a1--a的第一个值
a 3 a3:a的第三个值
b 1 b1--b的第一个值
b 3 b3:b的第三个值
b 2 b2b2b2b2
b 4 b4b4
b 5 b5b5b5b5b5
*/
--创建表并插入数据:
create table tb(name varchar(10),val int,memo varchar(20))
insert into tb values('a', 2, 'a2(a的第二个值)')
insert into tb values('a', 1, 'a1--a的第一个值')
insert into tb values('a', 3, 'a3:a的第三个值')
insert into tb values('b', 1, 'b1--b的第一个值')
insert into tb values('b', 3, 'b3:b的第三个值')
insert into tb values('b', 2, 'b2b2b2b2')
insert into tb values('b', 4, 'b4b4')
insert into tb values('b', 5, 'b5b5b5b5b5')
go--一、按name分组取val最大的值所在行的数据。
--方法1:
select a.* from tb a where val = (select max(val) from tb where name = a.name) order by a.name
--方法2:
select a.* from tb a where not exists(select 1 from tb where name = a.name and val > a.val)
--方法3:
select a.* from tb a,(select name,max(val) val from tb group by name) b where a.name = b.name and a.val = b.val order by a.name
--方法4:
select a.* from tb a inner join (select name , max(val) val from tb group by name) b on a.name = b.name and a.val = b.val order by a.name
--方法5
select a.* from tb a where 1 > (select count(*) from tb where name = a.name and val > a.val ) order by a.name
/*
name val memo
---------- ----------- --------------------
a 3 a3:a的第三个值
b 5 b5b5b5b5b5
*/--二、按name分组取val最小的值所在行的数据。
--方法1:
select a.* from tb a where val = (select min(val) from tb where name = a.name) order by a.name
--方法2:
select a.* from tb a where not exists(select 1 from tb where name = a.name and val < a.val)
--方法3:
select a.* from tb a,(select name,min(val) val from tb group by name) b where a.name = b.name and a.val = b.val order by a.name
--方法4:
select a.* from tb a inner join (select name , min(val) val from tb group by name) b on a.name = b.name and a.val = b.val order by a.name
--方法5
select a.* from tb a where 1 > (select count(*) from tb where name = a.name and val < a.val) order by a.name
/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
b 1 b1--b的第一个值
*/--三、按name分组取第一次出现的行所在的数据。
select a.* from tb a where val = (select top 1 val from tb where name = a.name) order by a.name
/*
name val memo
---------- ----------- --------------------
a 2 a2(a的第二个值)
b 1 b1--b的第一个值
*/--四、按name分组随机取一条数据。
select a.* from tb a where val = (select top 1 val from tb where name = a.name order by newid()) order by a.name
/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
b 5 b5b5b5b5b5
*/--五、按name分组取最小的两个(N个)val
select a.* from tb a where 2 > (select count(*) from tb where name = a.name and val < a.val ) order by a.name,a.val
select a.* from tb a where val in (select top 2 val from tb where name=a.name order by val) order by a.name,a.val
select a.* from tb a where exists (select count(*) from tb where name = a.name and val < a.val having Count(*) < 2) order by a.name,a.val
/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
a 2 a2(a的第二个值)
b 1 b1--b的第一个值
b 2 b2b2b2b2
*/--六、按name分组取最大的两个(N个)val
select a.* from tb a where 2 > (select count(*) from tb where name = a.name and val > a.val ) order by a.name,a.val
select a.* from tb a where val in (select top 2 val from tb where name=a.name order by val desc) order by a.name,a.val
select a.* from tb a where exists (select count(*) from tb where name = a.name and val > a.val having Count(*) < 2) order by a.name , a.val
/*
name val memo
---------- ----------- --------------------
a 2 a2(a的第二个值)
a 3 a3:a的第三个值
b 4 b4b4
b 5 b5b5b5b5b5
*/
--七,如果整行数据有重复,所有的列都相同。
/*
数据如下:
name val memo
a 2 a2(a的第二个值)
a 1 a1--a的第一个值
a 1 a1--a的第一个值
a 3 a3:a的第三个值
a 3 a3:a的第三个值
b 1 b1--b的第一个值
b 3 b3:b的第三个值
b 2 b2b2b2b2
b 4 b4b4
b 5 b5b5b5b5b5
*/
--在sql server 2000中只能用一个临时表来解决,生成一个自增列,先对val取最大或最小,然后再通过自增列来取数据。
--创建表并插入数据:
create table tb(name varchar(10),val int,memo varchar(20))
insert into tb values('a', 2, 'a2(a的第二个值)')
insert into tb values('a', 1, 'a1--a的第一个值')
insert into tb values('a', 1, 'a1--a的第一个值')
insert into tb values('a', 3, 'a3:a的第三个值')
insert into tb values('a', 3, 'a3:a的第三个值')
insert into tb values('b', 1, 'b1--b的第一个值')
insert into tb values('b', 3, 'b3:b的第三个值')
insert into tb values('b', 2, 'b2b2b2b2')
insert into tb values('b', 4, 'b4b4')
insert into tb values('b', 5, 'b5b5b5b5b5')
goselect * , px = identity(int,1,1) into tmp from tbselect m.name,m.val,m.memo from
(
select t.* from tmp t where val = (select min(val) from tmp where name = t.name)
) m where px = (select min(px) from
(
select t.* from tmp t where val = (select min(val) from tmp where name = t.name)
) n where n.name = m.name)drop table tb,tmp/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
b 1 b1--b的第一个值(2 行受影响)
*/
--在sql server 2005中可以使用row_number函数,不需要使用临时表。
--创建表并插入数据:
create table tb(name varchar(10),val int,memo varchar(20))
insert into tb values('a', 2, 'a2(a的第二个值)')
insert into tb values('a', 1, 'a1--a的第一个值')
insert into tb values('a', 1, 'a1--a的第一个值')
insert into tb values('a', 3, 'a3:a的第三个值')
insert into tb values('a', 3, 'a3:a的第三个值')
insert into tb values('b', 1, 'b1--b的第一个值')
insert into tb values('b', 3, 'b3:b的第三个值')
insert into tb values('b', 2, 'b2b2b2b2')
insert into tb values('b', 4, 'b4b4')
insert into tb values('b', 5, 'b5b5b5b5b5')
goselect m.name,m.val,m.memo from
(
select * , px = row_number() over(order by name , val) from tb
) m where px = (select min(px) from
(
select * , px = row_number() over(order by name , val) from tb
) n where n.name = m.name)drop table tb/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
b 1 b1--b的第一个值(2 行受影响)
*/
go
insert into tb SELECT 'SH001', '001', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-24 00:00:00.000' UNION ALL
SELECT 'SH001', '001', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-23 00:00:00.000' UNION ALL
SELECT 'SH001', '002', '2008-12-25 00:00:00.000' UNION ALL
SELECT 'SH001', 'aa', '2008-12-25 00:00:00.000'
go
select A,B,min(C) C
from tb
group by A,B