删除sqlserver中的重复记录并按照条件保存其中一条

时间：2022-06-29 08:05:19 编辑：袖梨来源：一聚教程网

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)

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