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删除sqlserver中的重复记录并按照条件保存其中一条

实施代码如下:

 代码如下 复制代码

SELECT *
FROM [extract].[dbo].[tbTradeFullinfoGet] WHERE tid IN
(SELECT tid
FROM [extract].[dbo].[tbTradeFullinfoGet]
GROUP BY tid
HAVING COUNT(tid) > 1 ) order by tid desc

select distinct tid,*  into #aaa from [extract].[dbo].[tbTradeFullinfoGet]
truncate table [extract].[dbo].[tbTradeFullinfoGet]
insert [extract].[dbo].[tbTradeFullinfoGet] select * from #aaa

delete from [extract].[dbo].[tbTradeFullinfoGet]
where tid in (select tid from [extract].[dbo].[tbTradeFullinfoGet] group by tid having count(tid) > 1)
and intime not in (select max(intime) from [extract].[dbo].[tbTradeFullinfoGet] group by tid having count(tid )>1)

select a.*,
ROW_NUMBER() over (partition by a.tid order by a.intime desc) as rows_id
into   ##test_a
from   [extract].[dbo].[tbTradeFullinfoGet] a

delete from ##test_a
where  rows_id<>'1'

alter table ##test_a drop column rows_id

drop table [extract].[dbo].[tbTradeFullinfoGet]

select *
into   [extract].[dbo].[tbTradeFullinfoGet]
from   ##test_a

代码的功能是删除tbTradeFullinfoGet里重复的记录,且只保存表中intime最大的一条记录!

其它一些删除重复记录sql语句


1、SQL Server查找表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断

 代码如下 复制代码
select * from people  where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)

2、删除表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断,只留有rowid最小的记录

 代码如下 复制代码

delete from people   where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)  and rowid not in (select min(rowid) from people group by peopleId having count(peopleId )>1 )

3、查找表中多余的重复记录(多个字段)

 代码如下 复制代码
select * from vitae a  where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)

4、删除表中多余的重复记录(多个字段),只留有rowid最小的记录

 代码如下 复制代码
delete from vitae a  where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)  and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)

5、SQL Server查找表中多余的重复记录(多个字段),不包含rowid最小的记录

 代码如下 复制代码

select * from vitae a  
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)  
and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)

补充一些知识

有两个意义上的重复记录,一是完全重复的记录,也即所有字段均重复的记录,二是部分关键字段重复的记录,比如Name字段重复,而其他字段不一定重复或都重复可以忽略。
1、对于第一种重复,比较容易解决,使用

 代码如下 复制代码
select distinct * from tableName

就可以得到无重复记录的结果集。
如果该表需要删除重复的记录(重复记录保留1条),可以按以下方法删除

 代码如下 复制代码
select distinct * into #Tmp from tableName
drop table tableName
select * into tableName from #Tmp
drop table #Tmp

发生这种重复的原因是表设计不周产生的,增加唯一索引列即可解决。
2、这类重复问题通常要求保留重复记录中的第一条记录,操作方法如下
假设有重复的字段为Name,Address,要求得到这两个字段唯一的结果集

 代码如下 复制代码
select identity(int,1,1) as autoID, * into #Tmp from tableName
select min(autoID) as autoID into #Tmp2 from #Tmp group by Name,autoID
select * from #Tmp where autoID in(select autoID from #tmp2)

最后一个select即得到了Name,Address不重复的结果集(但多了一个autoID字段,实际写时可以写在select子句中省去此列)
3、部分关键字段重复,且记录中有ID.
第一种方法可一次删除所有重复的..(只保留重复中ID最小的记录)。

 代码如下 复制代码
delete from table where id not in ( select min(id) from table group by name)

第二种方法每次只删除重复中ID最大的一条记录。

 代码如下 复制代码

delete from table where id in ( select max(id) from table group by name having count(*)>1)

补充:数据库,Mssql
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