Oracle 查询并删除重复记录的SQL语句

比眉伴天荒 2021-07-26 19:53 460阅读 0赞

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  
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)

注:rowid为oracle自带不用该.....

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(\*)>1)

(二)  
比方说  
在A表中存在一个字段“name”，  
而且不同记录之间的“name”值有可能会相同，  
现在就是需要查询出在该表中的各记录之间，“name”值存在重复的项；  
Select Name,Count(\*) From A Group By Name Having Count(\*) > 1

如果还查性别也相同大则如下:  
Select Name,sex,Count(\*) From A Group By Name,sex Having Count(\*) > 1

(三)  
方法一

declare @max integer,@id integer

declare cur\_rows cursor local for select 主字段,count(\*) from 表名 group by 主字段 having count(\*) >； 1

open cur\_rows

fetch cur\_rows into @id,@max

while @@fetch\_status=0

begin

select @max = @max -1

set rowcount @max

delete from 表名 where 主字段 = @id

fetch cur\_rows into @id,@max