insert into temp values(1,'tom',11,78);
insert into temp values(2,'lack',11,88);insert into temp values(3,'tom',11,78);
insert into temp values(4,'ttt',12,89);insert into temp values(5,'tim',12,89);
insert into temp values(6,'ttt',12,67);对应的列 分别试 id ,name ,class, score要求:删除表中姓名和班级都相同的人的信息,并保留其中id较大的那个人的信息????住:最好说说自己试怎么想出来的....3Q了!!!!
insert into temp values(2,'lack',11,88);insert into temp values(3,'tom',11,78);
insert into temp values(4,'ttt',12,89);insert into temp values(5,'tim',12,89);
insert into temp values(6,'ttt',12,67);对应的列 分别试 id ,name ,class, score要求:删除表中姓名和班级都相同的人的信息,并保留其中id较大的那个人的信息????住:最好说说自己试怎么想出来的....3Q了!!!!
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delete temp where id not in(select max(id) from temp group by name ,class)
delete temp where id in (select id from temp a,temp b where a.name=b.name and a.class=b.class) and id not in((select max(id) from (select id from temp a,temp b where a.name=b.name and a.class=b.class) as temp)随便写的没测试,大概意思就是删除掉姓名和班级相同的,同时要排除最大的那个
declare @table1 table
(
id int,
name varchar(10) ,
class int,
score int
)
insert into @table1 values(1,'tom',11,78);
insert into @table1 values(2,'lack',11,88); insert into @table1 values(3,'tom',11,78);
insert into @table1 values(4,'ttt',12,89); insert into @table1 values(5,'tim',12,89);
insert into @table1 values(6,'ttt',12,67); delete @table1 where id not in(select max(id) from @table1 group by name ,class)select * from @table1
insert into temp values(2,'lack',11,88); insert into temp values(3,'tom',11,78);
insert into temp values(4,'ttt',12,89); insert into temp values(5,'tim',12,89);
insert into temp values(6,'ttt',12,67); 对应的列 分别试 id ,name ,class, score 要求:删除表中姓名和班级都相同的人的信息,并保留其中id较大的那个人的信息???? 住:最好说说自己试怎么想出来的....3Q了!!!!-------------------------------
delete t
from temp t
where exists(
select 1 from temp
where name=t.name
and class=t.class
and t.id<id)
insert into temp values(1,'tom',11,78);
insert into temp values(2,'lack',11,88);insert into temp values(3,'tom',11,78);
insert into temp values(4,'ttt',12,89);insert into temp values(5,'tim',12,89);
insert into temp values(6,'ttt',12,67);select * from temp as a where not exists(select 1 from temp where name=a.name and class=a.class and id>a.id)drop table temp
/*
id name class score
----------- ----- ----------- -----------
2 lack 11 88
3 tom 11 78
5 tim 12 89
6 ttt 12 67
*/
go
create table [temp](id int ,name varchar(10),class varchar(10), score int )
insert into [temp] values(1,'tom',11,78);
insert into [temp] values(2,'lack',11,88);
insert into [temp] values(3,'tom',11,78);
insert into [temp] values(4,'ttt',12,89);
insert into [temp] values(5,'tim',12,89);
insert into [temp] values(6,'ttt',12,67);
delete t from temp t where exists(select 1 from temp where name=t.name and class=t.class and id>t.id)
select * from temp
/*
id name class score
----------- ---------- ---------- -----------
2 lack 11 88
3 tom 11 78
5 tim 12 89
6 ttt 12 67(影響 4 個資料列)*/
/******************************************************************************************************************************************************
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)
*/
declare @table1 table
(
id int,
name varchar(10) ,
class int,
score int
)
insert into @table1 values(1,'tom',11,78);
insert into @table1 values(2,'lack',11,88); insert into @table1 values(3,'tom',11,78);
insert into @table1 values(4,'ttt',12,89); insert into @table1 values(5,'tim',12,89);
insert into @table1 values(6,'ttt',12,67); delete @table1 where id no…
--这里我先假设你的表名为@temp
declare @temp table
(
id int,
name varchar(40),
class int,
score int
)insert into @temp values(1,'tom',11,78);
insert into @temp values(2,'lack',11,88); insert into @temp values(3,'tom',11,78);
insert into @temp values(4,'ttt',12,89); insert into @temp values(5,'tim',12,89);
insert into @temp values(6,'ttt',12,67); -----------上面是插入数据-----------当前如果你的库里面有数据了,就不用插入了delete from @temp ----删除内容---
where id not in( ------------这个是判断的ID不在 “姓名和班级都相同的人最大的ID”里面。 -------------这里面,是找到,“姓名和班级都相同的人”最大的ID
select max(id) from @temp
group by name,class
)select * from @temp -------删除后的结果
/*
如果这段代码,中的@temp换成你的,真正的表名就可以了。如换成 temp查询结果:
1.为了方便你看,我先写出--------------------------------------
select max(id) from @temp
group by name,class
代码的查询结果:
2
3
5
62.删除语句修改为查询语句,-----------------------------------select * from @temp
where id not in(
select max(id) from @temp
group by name,class
)
结果:
1 tom 11 78
4 ttt 12 893.执行--------------------------------------------------
delete from @temp
where id not in(
select max(id) from @temp
group by name,class
)select * from @temp
后的结果:
2 lack 11 88
3 tom 11 78
5 tim 12 89
6 ttt 12 67
*/
----找最大ID
(SELECT NAME, CLASS, max(ID)
FROM
(
SELECT 1 AS ID,'tom' AS NAME ,11 AS CLASS ,78 AS SCORE
UNION
SELECT 2 AS ID,'lack' AS NAME ,11 AS CLASS ,88 AS SCORE
UNION
SELECT 3 AS ID,'tom' AS NAME ,11 AS CLASS ,78 AS SCORE
UNION
SELECT 4 AS ID,'ttt' AS NAME ,12 AS CLASS ,89 AS SCORE
UNION
SELECT 5 AS ID,'tim' AS NAME ,12 AS CLASS ,89 AS SCORE
UNION
SELECT 6 AS ID,'ttt' AS NAME ,12 AS CLASS ,67 AS SCORE
) AS AA
GROUP BY NAME, CLASS
) As AAA// 找姓名班级组合出现次数 为 1以上的纪录。
(
SELECT NAME, CLASS, COUNT(*)AS FindCount
FROM
(
SELECT 1 AS ID,'tom' AS NAME ,11 AS CLASS ,78 AS SCORE
UNION
SELECT 2 AS ID,'lack' AS NAME ,11 AS CLASS ,88 AS SCORE
UNION
SELECT 3 AS ID,'tom' AS NAME ,11 AS CLASS ,78 AS SCORE
UNION
SELECT 4 AS ID,'ttt' AS NAME ,12 AS CLASS ,89 AS SCORE
UNION
SELECT 5 AS ID,'tim' AS NAME ,12 AS CLASS ,89 AS SCORE
UNION
SELECT 6 AS ID,'ttt' AS NAME ,12 AS CLASS ,67 AS SCORE
) AS AA
GROUP BY NAME, CLASS
) As BBB where bbb.FindCount =2
and bbb.name = aaa.name
bbb.class = aaa.class
and tmp.ID <> aaa.id
create table .....insert into table
(SELECT NAME, CLASS, max(ID)
FROM
(
SELECT 1 AS ID,'tom' AS NAME ,11 AS CLASS ,78 AS SCORE
UNION
SELECT 2 AS ID,'lack' AS NAME ,11 AS CLASS ,88 AS SCORE
UNION
SELECT 3 AS ID,'tom' AS NAME ,11 AS CLASS ,78 AS SCORE
UNION
SELECT 4 AS ID,'ttt' AS NAME ,12 AS CLASS ,89 AS SCORE
UNION
SELECT 5 AS ID,'tim' AS NAME ,12 AS CLASS ,89 AS SCORE
UNION
SELECT 6 AS ID,'ttt' AS NAME ,12 AS CLASS ,67 AS SCORE
) AS AA
GROUP BY NAME, CLASS
) As AAA // 找姓名班级组合出现次数 为 1以上的纪录。
create table2 .....insert into table2(
SELECT NAME, CLASS, COUNT(*)AS FindCount
FROM
(
SELECT 1 AS ID,'tom' AS NAME ,11 AS CLASS ,78 AS SCORE
UNION
SELECT 2 AS ID,'lack' AS NAME ,11 AS CLASS ,88 AS SCORE
UNION
SELECT 3 AS ID,'tom' AS NAME ,11 AS CLASS ,78 AS SCORE
UNION
SELECT 4 AS ID,'ttt' AS NAME ,12 AS CLASS ,89 AS SCORE
UNION
SELECT 5 AS ID,'tim' AS NAME ,12 AS CLASS ,89 AS SCORE
UNION
SELECT 6 AS ID,'ttt' AS NAME ,12 AS CLASS ,67 AS SCORE
) AS AA
GROUP BY NAME, CLASS
) As BBB
delete from tmp
where table2.FindCount =2
and table2.name = table.name
table2.class = table.class
and tmp.ID <> table.id
use test
go
if object_id('t') is not null
drop table t
go
create table t(id int,name varchar(100),class int,score int)
insert into t values(1,'tom',11,78)
insert into t values(2,'lack',11,88)insert into t values(3,'tom',11,78)
insert into t values(4,'ttt',12,89) insert into t values(5,'tim',12,89)
insert into t values(6,'ttt',12,67)
--解法1
select * from t a where not exists
(select * from t where t.name=a.name and t.class =a.class and t.id>a.id)select * from t b where id=(select max(id) from t where t.name=b.name and t.class =b.class )
--解法2
if object_id('fun_id') is not null
drop function fun_id
go
create function fun_id(@name varchar(100),@class int)
returns int
as
begin
declare @a int
select @a=(select max(id) from t where name=@name and class=cast(@class as int))
return @a
end
go
select * from t where id=dbo.fun_id(name,class)
id name class score
----------- ---------------------------------------------------------------------------------------------------- ----------- -----------
2 lack 11 88
3 tom 11 78
5 tim 12 89
6 ttt 12 67(4 行受影响)id name class score
----------- ---------------------------------------------------------------------------------------------------- ----------- -----------
6 ttt 12 67
3 tom 11 78
5 tim 12 89
2 lack 11 88(4 行受影响)id name class score
----------- ---------------------------------------------------------------------------------------------------- ----------- -----------
2 lack 11 88
3 tom 11 78
5 tim 12 89
6 ttt 12 67(4 行受影响)
就一个sql语句能写出这么多!
学到了不少知识!