SQL 查询和删除重复字段数据的方法

时间:2021-05-02

例如:
id name value
1 a pp
2 a pp
3 b iii
4 b pp
5 b pp
6 c pp
7 c pp
8 c iii
id是主键
要求得到这样的结果
id name value
1 a pp
3 b iii
4 b pp
6 c pp
8 c iii

方法1

复制代码 代码如下:


delete YourTable
where [id] not in (
select max([id]) from YourTable
group by (name + value))


方法2

复制代码 代码如下:


delete a
from 表 a left join(
select id=min(id) from 表 group by name,value
)b on a.id=b.id
where b.id is null

查询及删除重复记录的SQL语句
查询及删除重复记录的SQL语句
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

复制代码 代码如下:


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

复制代码 代码如下:


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)

复制代码 代码如下:


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

复制代码 代码如下:


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

复制代码 代码如下:

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