结构
Code DateTime ..............
1 2010-06-30 15:01:00
2 2010-06-29 10:00:00
1 2010-06-30 10:00:00 2 2010-06-29 06:00:00
........
1 2010-04-05 15:00:00.....................
要得到的数据是
要求: 某编号最大时间前一个月的每天的最后一条记录 如:
1 2010-06-30 15:01:00
1 2010-06-15 14:01:00
1 2010-06-10 06:01:00
......
2 2010-06-10 15:01:00
2 2010-05-30 12:01:00
2 2010-05-20 13:01:00
即 以每个编号的最大时间为准,向前取1个月的记录
Code DateTime ..............
1 2010-06-30 15:01:00
2 2010-06-29 10:00:00
1 2010-06-30 10:00:00 2 2010-06-29 06:00:00
........
1 2010-04-05 15:00:00.....................
要得到的数据是
要求: 某编号最大时间前一个月的每天的最后一条记录 如:
1 2010-06-30 15:01:00
1 2010-06-15 14:01:00
1 2010-06-10 06:01:00
......
2 2010-06-10 15:01:00
2 2010-05-30 12:01:00
2 2010-05-20 13:01:00
即 以每个编号的最大时间为准,向前取1个月的记录
select m.* from tb m,
(select t.* from tb t bwhere DateTime = (select max(DateTime) from tb where Code = t.Code)) n
where m.code = n.code and datediff(mm,m.DateTime,n.DateTime) <= 1
insert into tb values(1, '2010-06-30 15:01:00')
insert into tb values(2, '2010-06-29 10:00:00')
insert into tb values(1, '2010-06-30 10:00:00')
insert into tb values(2, '2010-06-29 06:00:00')
insert into tb values(1, '2010-04-05 15:00:00')
go--如果只按照月份算,则如下。
select m.* from tb m,
(select t.* from tb t where DateTime = (select max(DateTime) from tb where Code = t.Code)) n
where m.code = n.code and datediff(mm,m.DateTime,n.DateTime) <= 1
order by m.code , m.[DateTime] desc
/*
Code DateTime
----------- ------------------------------------------------------
1 2010-06-30 15:01:00.000
1 2010-06-30 10:00:00.000
2 2010-06-29 10:00:00.000
2 2010-06-29 06:00:00.000(所影响的行数为 4 行)
*/--如果需要按照日期算,则如下。
select m.* from tb m,
(select t.* from tb t where DateTime = (select max(DateTime) from tb where Code = t.Code)) n
where m.code = n.code and
((datediff(mm,m.DateTime,n.DateTime) = 0 and m.DateTime <= n.DateTime) or
(datediff(mm,m.DateTime,n.DateTime) = 1 and right(convert(varchar(19),m.DateTime,120),11) > right(convert(varchar(19),n.DateTime,120),11))
)
order by m.code , m.[DateTime] desc
/*
Code DateTime
----------- ------------------------------------------------------
1 2010-06-30 15:01:00.000
1 2010-06-30 10:00:00.000
2 2010-06-29 10:00:00.000
2 2010-06-29 06:00:00.000(所影响的行数为 4 行)
*/drop table tb
from tb a
join (select code,max([DateTime]) as dt from tb group by code) b
on a.code=b.code
where a.[datetime]<=b.dt and a.[datetime]>=dateadd(mm,-1,b.dt)
insert into tb values(1, '2010-06-30 15:01:00')
insert into tb values(2, '2010-06-29 10:00:00')
insert into tb values(1, '2010-06-30 10:00:00')
insert into tb values(2, '2010-06-29 06:00:00')
insert into tb values(1, '2010-04-05 15:00:00')
go--如果只按照月份算,则如下。
select m.* from tb m,
(select t.* from tb t where DateTime = (select max(DateTime) from tb where Code = t.Code)) n
where m.code = n.code and datediff(mm,m.DateTime,n.DateTime) <= 1
order by m.code , m.[DateTime] desc
/*
Code DateTime
----------- ------------------------------------------------------
1 2010-06-30 15:01:00.000
1 2010-06-30 10:00:00.000
2 2010-06-29 10:00:00.000
2 2010-06-29 06:00:00.000(所影响的行数为 4 行)
*/--如果需要按照日期算,则如下。
select m.* from tb m,
(select t.* from tb t where DateTime = (select max(DateTime) from tb where Code = t.Code)) n
where m.code = n.code and
((datediff(mm,m.DateTime,n.DateTime) = 0 and m.DateTime <= n.DateTime) or
(datediff(mm,m.DateTime,n.DateTime) = 1 and right(convert(varchar(19),m.DateTime,120),11) > right(convert(varchar(19),n.DateTime,120),11))
)
order by m.code , m.[DateTime] desc
/*
Code DateTime
----------- ------------------------------------------------------
1 2010-06-30 15:01:00.000
1 2010-06-30 10:00:00.000
2 2010-06-29 10:00:00.000
2 2010-06-29 06:00:00.000(所影响的行数为 4 行)
*/--获取所有每天的最后一条记录,不分code.
select t.* from tb t where DateTime = (select max(DateTime) from tb where convert(varchar(10),DateTime,120) = convert(varchar(10),t.DateTime,120))
/*
Code DateTime
----------- ------------------------------------------------------
1 2010-06-30 15:01:00.000
2 2010-06-29 10:00:00.000
1 2010-04-05 15:00:00.000(所影响的行数为 3 行)
*/--获取所有每天的最后一条记录,分code.
select t.* from tb t where DateTime = (select max(DateTime) from tb where code = t.code and convert(varchar(10),DateTime,120) = convert(varchar(10),t.DateTime,120))
/*
Code DateTime
----------- ------------------------------------------------------
1 2010-06-30 15:01:00.000
2 2010-06-29 10:00:00.000
1 2010-04-05 15:00:00.000(所影响的行数为 3 行)
*/drop table tb
--(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)
*/
1、 先创建两个视图:
Create VIEW dbo.tb_V_1 AS SELECT code, CONVERT(varchar(10), datetime, 120) AS num, MAX(datetime) AS datetime FROM dbo.tbGROUP BY code, CONVERT(varchar(10), datetime, 120)Create VIEW dbo.tb_V_2
AS
SELECT code, MAX(datetime) AS datetime
FROM dbo.tb
GROUP BY code2、然后 用
SELECT a.code, a.datetime
FROM dbo.tb_V_1 a RIGHT OUTER JOIN
dbo.tb_V_2 b ON a.code = b.code
WHERE (DATEDIFF(mm, a.datetime, b.datetime) <= 1)
--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