sql中怎么删除两条重复记录并保留一条

将数据去重复后暂存到临时表#a中

select distinct * into #a from table1 where 条件

delete table1 where 删除限制条件

insert into table1 select * from #a -将暂存的数据插回数据库

drop table #a -删除临时表

注：当前的数据库，每一个表都应该有一个标志字段，以保证记录不完全重复，否则实用中极易出问题。

扩展资料：

SQL语句删除掉重复的其他情况

1、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

SELECT

*

FROM

people

WHERE

peopleId IN (

SELECT

peopleId

FROM

people

GROUP BY

peopleId

HAVING

count(peopleId) >1

)

2、查找表中多余的重复记录（多个字段）

SELECT

*

FROM

vitae a

WHERE

(a.peopleId, a.seq) IN (

SELECT

peopleId,

seq

FROM

vitae

GROUP BY

peopleId,

seq

HAVING

count(*) >1

)

参考资料来源：结构化查询语言（SQL）-百度百科

sql查询去除重复值语句

sql 单表/多表查询去除重复记录

单表distinct

多表group by

group by 必须放在 order by 和 limit之前，不然会报错

************************************************************************************

1、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

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

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）

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

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、查找表中多余的重复记录（多个字段），不包含rowid最小的记录

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(*)>

你要先找到规律，并且有确定的限制条件。是否所有的重复数据都删了只留一条？旧数据和新数据的界定是什么？是某个时刻？那旧数据中有重复数据删不删？重复数据是指仅仅title字段信息一样？

如果是在工作上，删除数据是一项很严谨的事，这个你必须要想清楚所有的条件情况，只是这样几句话，让网友给个sql语句，直接用上去，害的是你自己。

也不知道你的数据库具体是怎么样的，给个一般删除重复数据的方法

select distinct * into #Tmp_aa from tableName 把不重复的找出来插入到临时表

drop table tableName删掉原来的表

select * into tableName from #Tmp_aa把临时表插入到新建的tableName

drop table #Tmp_aa 删掉临时表

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