ID sub_ID RQ
1 1 2012-1-1
1 2 2012-9-2
1 3 2012-1-3
2 1 2012-5-6
2 2 2012-1-2
3 1 2012-10-1
3 2 2012-1-2
3 3 2012-1-5
3 4 2012-11-9
需要用一个SQL语句得到:
ID sub_ID RQ
1 2 2012-9-2
2 1 2012-5-6
3 4 2012-11-9
怎么写SQL语句呢?
12 个解决方案
#1
select *
from tb t
where rq=(select max(rq) from tb where id=t.id)
#2
日期有可能是会重复!!!!!!!!!
#3
select ID,sub_ID,RQ from
(select *,row_number()over(partition by ID order by RQ desc) as num from tbl)a where num=1
#4
select distinct ID,sub_ID,RQ from
(select *,row_number()over(partition by ID order by RQ desc) as num from tbl)a where num=1
(select *,row_number()over(partition by ID order by RQ desc) as num from tbl)a where num=1
#5
sql有这个函数么? 貌似oracle才行吧?
1L应该满足了
#6
汗,2005以上版本有,这个还怀疑???
#7
N种方法实现这种需求,个人比较喜欢用这个
#8
--处理表重复记录(查询和删除)
/******************************************************************************************************************************************************
1、Num、Name相同的重复值记录,没有大小关系只保留一条
2、Name相同,ID有大小关系时,保留大或小其中一个记录
整理人:中国风(Roy)
日期:2008.06.06
******************************************************************************************************************************************************/
--1、用于查询重复处理记录(如果列没有大小关系时2000用生成自增列和临时表处理,SQL2005用row_number函数处理)
--> --> (Roy)生成測試數據
if not object_id('Tempdb..#T') is null
drop table #T
Go
Create table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))
Insert #T
select 1,N'A',N'A1' union all
select 2,N'A',N'A2' union all
select 3,N'A',N'A3' union all
select 4,N'B',N'B1' union all
select 5,N'B',N'B2'
Go
--I、Name相同ID最小的记录(推荐用1,2,3),方法3在SQl05时,效率高于1、2
方法1:
Select * from #T a where not exists(select 1 from #T where Name=a.Name and ID<a.ID)
方法2:
select a.* from #T a join (select min(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID
方法3:
select * from #T a where ID=(select min(ID) from #T where Name=a.Name)
方法4:
select a.* from #T a join #T b on a.Name=b.Name and a.ID>=b.ID group by a.ID,a.Name,a.Memo having count(1)=1
方法5:
select * from #T a group by ID,Name,Memo having ID=(select min(ID)from #T where Name=a.Name)
方法6:
select * from #T a where (select count(1) from #T where Name=a.Name and ID<a.ID)=0
方法7:
select * from #T a where ID=(select top 1 ID from #T where Name=a.name order by ID)
方法8:
select * from #T a where ID!>all(select ID from #T where Name=a.Name)
方法9(注:ID为唯一时可用):
select * from #T a where ID in(select min(ID) from #T group by Name)
--SQL2005:
方法10:
select ID,Name,Memo from (select *,min(ID)over(partition by Name) as MinID from #T a)T where ID=MinID
方法11:
select ID,Name,Memo from (select *,row_number()over(partition by Name order by ID) as MinID from #T a)T where MinID=1
生成结果:
/*
ID Name Memo
----------- ---- ----
1 A A1
4 B B1
(2 行受影响)
*/
--II、Name相同ID最大的记录,与min相反:
方法1:
Select * from #T a where not exists(select 1 from #T where Name=a.Name and ID>a.ID)
方法2:
select a.* from #T a join (select max(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID order by ID
方法3:
select * from #T a where ID=(select max(ID) from #T where Name=a.Name) order by ID
方法4:
select a.* from #T a join #T b on a.Name=b.Name and a.ID<=b.ID group by a.ID,a.Name,a.Memo having count(1)=1
方法5:
select * from #T a group by ID,Name,Memo having ID=(select max(ID)from #T where Name=a.Name)
方法6:
select * from #T a where (select count(1) from #T where Name=a.Name and ID>a.ID)=0
方法7:
select * from #T a where ID=(select top 1 ID from #T where Name=a.name order by ID desc)
方法8:
select * from #T a where ID!<all(select ID from #T where Name=a.Name)
方法9(注:ID为唯一时可用):
select * from #T a where ID in(select max(ID) from #T group by Name)
--SQL2005:
方法10:
select ID,Name,Memo from (select *,max(ID)over(partition by Name) as MinID from #T a)T where ID=MinID
方法11:
select ID,Name,Memo from (select *,row_number()over(partition by Name order by ID desc) as MinID from #T a)T where MinID=1
生成结果2:
/*
ID Name Memo
----------- ---- ----
3 A A3
5 B B2
(2 行受影响)
*/
--2、删除重复记录有大小关系时,保留大或小其中一个记录
--> --> (Roy)生成測試數據
if not object_id('Tempdb..#T') is null
drop table #T
Go
Create table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))
Insert #T
select 1,N'A',N'A1' union all
select 2,N'A',N'A2' union all
select 3,N'A',N'A3' union all
select 4,N'B',N'B1' union all
select 5,N'B',N'B2'
Go
--I、Name相同ID最小的记录(推荐用1,2,3),保留最小一条
方法1:
delete a from #T a where exists(select 1 from #T where Name=a.Name and ID<a.ID)
方法2:
delete a from #T a left join (select min(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID where b.Id is null
方法3:
delete a from #T a where ID not in (select min(ID) from #T where Name=a.Name)
方法4(注:ID为唯一时可用):
delete a from #T a where ID not in(select min(ID)from #T group by Name)
方法5:
delete a from #T a where (select count(1) from #T where Name=a.Name and ID<a.ID)>0
方法6:
delete a from #T a where ID<>(select top 1 ID from #T where Name=a.name order by ID)
方法7:
delete a from #T a where ID>any(select ID from #T where Name=a.Name)
select * from #T
生成结果:
/*
ID Name Memo
----------- ---- ----
1 A A1
4 B B1
(2 行受影响)
*/
--II、Name相同ID保留最大的一条记录:
方法1:
delete a from #T a where exists(select 1 from #T where Name=a.Name and ID>a.ID)
方法2:
delete a from #T a left join (select max(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID where b.Id is null
方法3:
delete a from #T a where ID not in (select max(ID) from #T where Name=a.Name)
方法4(注:ID为唯一时可用):
delete a from #T a where ID not in(select max(ID)from #T group by Name)
方法5:
delete a from #T a where (select count(1) from #T where Name=a.Name and ID>a.ID)>0
方法6:
delete a from #T a where ID<>(select top 1 ID from #T where Name=a.name order by ID desc)
方法7:
delete a from #T a where ID<any(select ID from #T where Name=a.Name)
select * from #T
/*
ID Name Memo
----------- ---- ----
3 A A3
5 B B2
(2 行受影响)
*/
--3、删除重复记录没有大小关系时,处理重复值
--> --> (Roy)生成測試數據
if not object_id('Tempdb..#T') is null
drop table #T
Go
Create table #T([Num] int,[Name] nvarchar(1))
Insert #T
select 1,N'A' union all
select 1,N'A' union all
select 1,N'A' union all
select 2,N'B' union all
select 2,N'B'
Go
方法1:
if object_id('Tempdb..#') is not null
drop table #
Select distinct * into # from #T--排除重复记录结果集生成临时表#
truncate table #T--清空表
insert #T select * from # --把临时表#插入到表#T中
--查看结果
select * from #T
/*
Num Name
----------- ----
1 A
2 B
(2 行受影响)
*/
--重新执行测试数据后用方法2
方法2:
alter table #T add ID int identity--新增标识列
go
delete a from #T a where exists(select 1 from #T where Num=a.Num and Name=a.Name and ID>a.ID)--只保留一条记录
go
alter table #T drop column ID--删除标识列
--查看结果
select * from #T
/*
Num Name
----------- ----
1 A
2 B
(2 行受影响)
*/
--重新执行测试数据后用方法3
方法3:
declare Roy_Cursor cursor local for
select count(1)-1,Num,Name from #T group by Num,Name having count(1)>1
declare @con int,@Num int,@Name nvarchar(1)
open Roy_Cursor
fetch next from Roy_Cursor into @con,@Num,@Name
while @@Fetch_status=0
begin
set rowcount @con;
delete #T where Num=@Num and Name=@Name
set rowcount 0;
fetch next from Roy_Cursor into @con,@Num,@Name
end
close Roy_Cursor
deallocate Roy_Cursor
--查看结果
select * from #T
/*
Num Name
----------- ----
1 A
2 B
(2 行受影响)
*/
#9
/*
ID sub_ID RQ
1 1 2012-1-1
1 2 2012-9-2
1 3 2012-1-3
2 1 2012-5-6
2 2 2012-1-2
3 1 2012-10-1
3 2 2012-1-2
3 3 2012-1-5
3 4 2012-11-9
需要用一个SQL语句得到:
ID sub_ID RQ
1 2 2012-9-2
2 1 2012-5-6
3 4 2012-11-9
怎么写SQL语句呢?
*/
go
if OBJECT_ID('tbl')is not null
drop table tbl
go
create table tbl(
ID int,
sub_ID int,
RQ date
)
go
insert tbl
select 1,1,'2012-1-1' union all
select 1,2,'2012-9-2' union all
select 1,3,'2012-1-3' union all
select 2,1,'2012-5-6' union all
select 2,2,'2012-1-2' union all
select 3,1,'2012-10-1' union all
select 3,2,'2012-1-2' union all
select 3,3,'2012-1-5' union all
select 3,4,'2012-11-9'
--方法一:
select ID,sub_ID,RQ from
(select *,row_number()over(partition by ID order by RQ desc) as num from tbl)a where num=1
--方法二:
select a.ID,sub_ID,a.RQ from tbl
inner join
(select ID,max(RQ) as RQ from tbl group by ID)a
on a.ID=tbl.ID and a.RQ=tbl.RQ
--方法三:
select *from tbl a where RQ in(select max(RQ) from tbl b where a.ID=b.ID)
/*
结果:
ID sub_ID RQ
1 2 2012-09-02
2 1 2012-05-06
3 4 2012-11-09
*/
ID sub_ID RQ
1 1 2012-1-1
1 2 2012-9-2
1 3 2012-1-3
2 1 2012-5-6
2 2 2012-1-2
3 1 2012-10-1
3 2 2012-1-2
3 3 2012-1-5
3 4 2012-11-9
需要用一个SQL语句得到:
ID sub_ID RQ
1 2 2012-9-2
2 1 2012-5-6
3 4 2012-11-9
怎么写SQL语句呢?
*/
go
if OBJECT_ID('tbl')is not null
drop table tbl
go
create table tbl(
ID int,
sub_ID int,
RQ date
)
go
insert tbl
select 1,1,'2012-1-1' union all
select 1,2,'2012-9-2' union all
select 1,3,'2012-1-3' union all
select 2,1,'2012-5-6' union all
select 2,2,'2012-1-2' union all
select 3,1,'2012-10-1' union all
select 3,2,'2012-1-2' union all
select 3,3,'2012-1-5' union all
select 3,4,'2012-11-9'
--方法一:
select ID,sub_ID,RQ from
(select *,row_number()over(partition by ID order by RQ desc) as num from tbl)a where num=1
--方法二:
select a.ID,sub_ID,a.RQ from tbl
inner join
(select ID,max(RQ) as RQ from tbl group by ID)a
on a.ID=tbl.ID and a.RQ=tbl.RQ
--方法三:
select *from tbl a where RQ in(select max(RQ) from tbl b where a.ID=b.ID)
/*
结果:
ID sub_ID RQ
1 2 2012-09-02
2 1 2012-05-06
3 4 2012-11-09
*/
#10
SELECT * FROM TB WHERE rq IN (SELECT max(rq) FROM TB group by ID)
#11
用RANK()函数..不是说日期有可能重复么..最大的日期并且相同的 会排同一个位置
#12
认真看问题,虽然没有解决,但是胡乱提交答案,或回答的驴唇不对马嘴的人,好多了!
#1
select *
from tb t
where rq=(select max(rq) from tb where id=t.id)
#2
日期有可能是会重复!!!!!!!!!
#3
select ID,sub_ID,RQ from
(select *,row_number()over(partition by ID order by RQ desc) as num from tbl)a where num=1
#4
select distinct ID,sub_ID,RQ from
(select *,row_number()over(partition by ID order by RQ desc) as num from tbl)a where num=1
(select *,row_number()over(partition by ID order by RQ desc) as num from tbl)a where num=1
#5
sql有这个函数么? 貌似oracle才行吧?
1L应该满足了
#6
汗,2005以上版本有,这个还怀疑???
#7
N种方法实现这种需求,个人比较喜欢用这个
#8
--处理表重复记录(查询和删除)
/******************************************************************************************************************************************************
1、Num、Name相同的重复值记录,没有大小关系只保留一条
2、Name相同,ID有大小关系时,保留大或小其中一个记录
整理人:中国风(Roy)
日期:2008.06.06
******************************************************************************************************************************************************/
--1、用于查询重复处理记录(如果列没有大小关系时2000用生成自增列和临时表处理,SQL2005用row_number函数处理)
--> --> (Roy)生成測試數據
if not object_id('Tempdb..#T') is null
drop table #T
Go
Create table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))
Insert #T
select 1,N'A',N'A1' union all
select 2,N'A',N'A2' union all
select 3,N'A',N'A3' union all
select 4,N'B',N'B1' union all
select 5,N'B',N'B2'
Go
--I、Name相同ID最小的记录(推荐用1,2,3),方法3在SQl05时,效率高于1、2
方法1:
Select * from #T a where not exists(select 1 from #T where Name=a.Name and ID<a.ID)
方法2:
select a.* from #T a join (select min(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID
方法3:
select * from #T a where ID=(select min(ID) from #T where Name=a.Name)
方法4:
select a.* from #T a join #T b on a.Name=b.Name and a.ID>=b.ID group by a.ID,a.Name,a.Memo having count(1)=1
方法5:
select * from #T a group by ID,Name,Memo having ID=(select min(ID)from #T where Name=a.Name)
方法6:
select * from #T a where (select count(1) from #T where Name=a.Name and ID<a.ID)=0
方法7:
select * from #T a where ID=(select top 1 ID from #T where Name=a.name order by ID)
方法8:
select * from #T a where ID!>all(select ID from #T where Name=a.Name)
方法9(注:ID为唯一时可用):
select * from #T a where ID in(select min(ID) from #T group by Name)
--SQL2005:
方法10:
select ID,Name,Memo from (select *,min(ID)over(partition by Name) as MinID from #T a)T where ID=MinID
方法11:
select ID,Name,Memo from (select *,row_number()over(partition by Name order by ID) as MinID from #T a)T where MinID=1
生成结果:
/*
ID Name Memo
----------- ---- ----
1 A A1
4 B B1
(2 行受影响)
*/
--II、Name相同ID最大的记录,与min相反:
方法1:
Select * from #T a where not exists(select 1 from #T where Name=a.Name and ID>a.ID)
方法2:
select a.* from #T a join (select max(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID order by ID
方法3:
select * from #T a where ID=(select max(ID) from #T where Name=a.Name) order by ID
方法4:
select a.* from #T a join #T b on a.Name=b.Name and a.ID<=b.ID group by a.ID,a.Name,a.Memo having count(1)=1
方法5:
select * from #T a group by ID,Name,Memo having ID=(select max(ID)from #T where Name=a.Name)
方法6:
select * from #T a where (select count(1) from #T where Name=a.Name and ID>a.ID)=0
方法7:
select * from #T a where ID=(select top 1 ID from #T where Name=a.name order by ID desc)
方法8:
select * from #T a where ID!<all(select ID from #T where Name=a.Name)
方法9(注:ID为唯一时可用):
select * from #T a where ID in(select max(ID) from #T group by Name)
--SQL2005:
方法10:
select ID,Name,Memo from (select *,max(ID)over(partition by Name) as MinID from #T a)T where ID=MinID
方法11:
select ID,Name,Memo from (select *,row_number()over(partition by Name order by ID desc) as MinID from #T a)T where MinID=1
生成结果2:
/*
ID Name Memo
----------- ---- ----
3 A A3
5 B B2
(2 行受影响)
*/
--2、删除重复记录有大小关系时,保留大或小其中一个记录
--> --> (Roy)生成測試數據
if not object_id('Tempdb..#T') is null
drop table #T
Go
Create table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))
Insert #T
select 1,N'A',N'A1' union all
select 2,N'A',N'A2' union all
select 3,N'A',N'A3' union all
select 4,N'B',N'B1' union all
select 5,N'B',N'B2'
Go
--I、Name相同ID最小的记录(推荐用1,2,3),保留最小一条
方法1:
delete a from #T a where exists(select 1 from #T where Name=a.Name and ID<a.ID)
方法2:
delete a from #T a left join (select min(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID where b.Id is null
方法3:
delete a from #T a where ID not in (select min(ID) from #T where Name=a.Name)
方法4(注:ID为唯一时可用):
delete a from #T a where ID not in(select min(ID)from #T group by Name)
方法5:
delete a from #T a where (select count(1) from #T where Name=a.Name and ID<a.ID)>0
方法6:
delete a from #T a where ID<>(select top 1 ID from #T where Name=a.name order by ID)
方法7:
delete a from #T a where ID>any(select ID from #T where Name=a.Name)
select * from #T
生成结果:
/*
ID Name Memo
----------- ---- ----
1 A A1
4 B B1
(2 行受影响)
*/
--II、Name相同ID保留最大的一条记录:
方法1:
delete a from #T a where exists(select 1 from #T where Name=a.Name and ID>a.ID)
方法2:
delete a from #T a left join (select max(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID where b.Id is null
方法3:
delete a from #T a where ID not in (select max(ID) from #T where Name=a.Name)
方法4(注:ID为唯一时可用):
delete a from #T a where ID not in(select max(ID)from #T group by Name)
方法5:
delete a from #T a where (select count(1) from #T where Name=a.Name and ID>a.ID)>0
方法6:
delete a from #T a where ID<>(select top 1 ID from #T where Name=a.name order by ID desc)
方法7:
delete a from #T a where ID<any(select ID from #T where Name=a.Name)
select * from #T
/*
ID Name Memo
----------- ---- ----
3 A A3
5 B B2
(2 行受影响)
*/
--3、删除重复记录没有大小关系时,处理重复值
--> --> (Roy)生成測試數據
if not object_id('Tempdb..#T') is null
drop table #T
Go
Create table #T([Num] int,[Name] nvarchar(1))
Insert #T
select 1,N'A' union all
select 1,N'A' union all
select 1,N'A' union all
select 2,N'B' union all
select 2,N'B'
Go
方法1:
if object_id('Tempdb..#') is not null
drop table #
Select distinct * into # from #T--排除重复记录结果集生成临时表#
truncate table #T--清空表
insert #T select * from # --把临时表#插入到表#T中
--查看结果
select * from #T
/*
Num Name
----------- ----
1 A
2 B
(2 行受影响)
*/
--重新执行测试数据后用方法2
方法2:
alter table #T add ID int identity--新增标识列
go
delete a from #T a where exists(select 1 from #T where Num=a.Num and Name=a.Name and ID>a.ID)--只保留一条记录
go
alter table #T drop column ID--删除标识列
--查看结果
select * from #T
/*
Num Name
----------- ----
1 A
2 B
(2 行受影响)
*/
--重新执行测试数据后用方法3
方法3:
declare Roy_Cursor cursor local for
select count(1)-1,Num,Name from #T group by Num,Name having count(1)>1
declare @con int,@Num int,@Name nvarchar(1)
open Roy_Cursor
fetch next from Roy_Cursor into @con,@Num,@Name
while @@Fetch_status=0
begin
set rowcount @con;
delete #T where Num=@Num and Name=@Name
set rowcount 0;
fetch next from Roy_Cursor into @con,@Num,@Name
end
close Roy_Cursor
deallocate Roy_Cursor
--查看结果
select * from #T
/*
Num Name
----------- ----
1 A
2 B
(2 行受影响)
*/
#9
/*
ID sub_ID RQ
1 1 2012-1-1
1 2 2012-9-2
1 3 2012-1-3
2 1 2012-5-6
2 2 2012-1-2
3 1 2012-10-1
3 2 2012-1-2
3 3 2012-1-5
3 4 2012-11-9
需要用一个SQL语句得到:
ID sub_ID RQ
1 2 2012-9-2
2 1 2012-5-6
3 4 2012-11-9
怎么写SQL语句呢?
*/
go
if OBJECT_ID('tbl')is not null
drop table tbl
go
create table tbl(
ID int,
sub_ID int,
RQ date
)
go
insert tbl
select 1,1,'2012-1-1' union all
select 1,2,'2012-9-2' union all
select 1,3,'2012-1-3' union all
select 2,1,'2012-5-6' union all
select 2,2,'2012-1-2' union all
select 3,1,'2012-10-1' union all
select 3,2,'2012-1-2' union all
select 3,3,'2012-1-5' union all
select 3,4,'2012-11-9'
--方法一:
select ID,sub_ID,RQ from
(select *,row_number()over(partition by ID order by RQ desc) as num from tbl)a where num=1
--方法二:
select a.ID,sub_ID,a.RQ from tbl
inner join
(select ID,max(RQ) as RQ from tbl group by ID)a
on a.ID=tbl.ID and a.RQ=tbl.RQ
--方法三:
select *from tbl a where RQ in(select max(RQ) from tbl b where a.ID=b.ID)
/*
结果:
ID sub_ID RQ
1 2 2012-09-02
2 1 2012-05-06
3 4 2012-11-09
*/
ID sub_ID RQ
1 1 2012-1-1
1 2 2012-9-2
1 3 2012-1-3
2 1 2012-5-6
2 2 2012-1-2
3 1 2012-10-1
3 2 2012-1-2
3 3 2012-1-5
3 4 2012-11-9
需要用一个SQL语句得到:
ID sub_ID RQ
1 2 2012-9-2
2 1 2012-5-6
3 4 2012-11-9
怎么写SQL语句呢?
*/
go
if OBJECT_ID('tbl')is not null
drop table tbl
go
create table tbl(
ID int,
sub_ID int,
RQ date
)
go
insert tbl
select 1,1,'2012-1-1' union all
select 1,2,'2012-9-2' union all
select 1,3,'2012-1-3' union all
select 2,1,'2012-5-6' union all
select 2,2,'2012-1-2' union all
select 3,1,'2012-10-1' union all
select 3,2,'2012-1-2' union all
select 3,3,'2012-1-5' union all
select 3,4,'2012-11-9'
--方法一:
select ID,sub_ID,RQ from
(select *,row_number()over(partition by ID order by RQ desc) as num from tbl)a where num=1
--方法二:
select a.ID,sub_ID,a.RQ from tbl
inner join
(select ID,max(RQ) as RQ from tbl group by ID)a
on a.ID=tbl.ID and a.RQ=tbl.RQ
--方法三:
select *from tbl a where RQ in(select max(RQ) from tbl b where a.ID=b.ID)
/*
结果:
ID sub_ID RQ
1 2 2012-09-02
2 1 2012-05-06
3 4 2012-11-09
*/
#10
SELECT * FROM TB WHERE rq IN (SELECT max(rq) FROM TB group by ID)
#11
用RANK()函数..不是说日期有可能重复么..最大的日期并且相同的 会排同一个位置
#12
认真看问题,虽然没有解决,但是胡乱提交答案,或回答的驴唇不对马嘴的人,好多了!