• 全部
  • 基础类
  • 应用实例
  • 新技术前沿

求个删除重复记录的查询

JJkukow 2008-04-04 03:07:32


use tempdb
go

if object_id('tempdb.dbo.t1') is not null drop table t1
create table t1 (id int identity(1,1),staff_id varchar(10),sign_time datetime)
insert into t1 select '2004033','2005-01-01 10:22:21'
union all select '2004033','2008-03-20 08:25:00'
union all select '2004033','2008-03-20 08:26:00'
union all select '2004033','2008-03-20 08:27:00'
union all select '2004033','2008-03-20 08:35:00'
union all select '2004033','2008-03-20 08:24:00'
union all select '2004033','2008-03-20 08:25:01'
union all select '2004033','2008-03-20 08:30:00'
union all select '2004033','2008-03-20 08:30:01'
union all select '2004033','2008-03-20 17:30:00'

select * from t1 order by 2,3

declare @dt1 datetime,@dt2 datetime
declare @se int
set @dt1='2005-01-01'
set @dt2='2008-08-01'
set @se=4



--删除在日期@dt1,@dt2范围内,时间相差@se内相同的数据,并保留第一条数据.
--执行结果


/*

1 2004033 2005-01-01 10:22:21
6 2004033 2008-03-20 08:24:00
8 2004033 2008-03-20 08:30:00
5 2004033 2008-03-20 08:35:00
10 2004033 2008-03-20 17:30:00
*/


--如何写这个删除语句,请教
...全文
88 点赞 收藏 6
写回复
6 条回复
切换为时间正序
当前发帖距今超过3年,不再开放新的回复
发表回复
JJkukow 2008-04-04
我写了个
delete a from t1 a where exists (select 1 from t1 where staff_id=a.staff_id and sign_time<a.sign_time and datediff(minute,sign_time,a.sign_time)<=@se and convert(varchar(10),sign_time,120) between @dt1 and @dt2)

结果就是不对.
你们SQL怎么那么厉害.咋学的啊?
回复
sasalar 2008-04-04
只学过用select distinct ? from ??
回复
JJkukow 2008-04-04
高手啊,我研究了那么久,你两分钟都搞定了,郁闷....
回复
viva369 2008-04-04
up楼上的~
回复
-狙击手- 2008-04-04

create table t1 (id int identity(1,1),staff_id varchar(10),sign_time datetime)
insert into t1 select '2004033','2005-01-01 10:22:21'
union all select '2004033','2008-03-20 08:25:00'
union all select '2004033','2008-03-20 08:26:00'
union all select '2004033','2008-03-20 08:27:00'
union all select '2004033','2008-03-20 08:35:00'
union all select '2004033','2008-03-20 08:24:00'
union all select '2004033','2008-03-20 08:25:01'
union all select '2004033','2008-03-20 08:30:00'
union all select '2004033','2008-03-20 08:30:01'
union all select '2004033','2008-03-20 17:30:00'



declare @dt1 datetime,@dt2 datetime
declare @se int
set @dt1='2005-01-01'
set @dt2='2008-08-01'
set @se=4



select *,datediff(mi,@dt1,sign_time)/@se as px
into #
from t1
order by datediff(mi,@dt1,sign_time)/@se,sign_time


select id,staff_id,sign_time
from # a
where not exists(select 1 from # where staff_id = a.staff_id and px = a.px and sign_time < a.sign_time)
if object_id('t1') is not null drop table t1
drop table #

/*
id staff_id sign_time
----------- ---------- ------------------------------------------------------
1 2004033 2005-01-01 10:22:21.000
6 2004033 2008-03-20 08:24:00.000
8 2004033 2008-03-20 08:30:00.000
5 2004033 2008-03-20 08:35:00.000
10 2004033 2008-03-20 17:30:00.000

(所影响的行数为 5 行)
*/
回复
liangCK 2008-04-04
--按某一字段分组取最大(小)值所在行的数据
(爱新觉罗.毓华 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
/*
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
/*
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')
go

select * , px = identity(int,1,1) into tmp from tb

select 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')
go

select 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)
*/
回复
相关推荐
发帖
MS-SQL Server
创建于2007-09-28

3.3w+

社区成员

MS-SQL Server相关内容讨论专区
申请成为版主
帖子事件
创建了帖子
2008-04-04 03:07
社区公告
暂无公告