在Oracle中,可以利用count()函数来查询重复字段,语法为“select * from 表名 where 字段 in(select 字段 from 表名 group by 字段 having count(字段) >1)”。
本教程操作环境:Windows10系统、Oracle 11g版、Dell G3电脑。
Oracle怎样查询重复字段
1、查找表中多余的重复记录,重复记录是根据单个字段(userCode)来判断
select
*
from
user
where
userCode
in
(select userCode from user group by userCode having count (userCode) > 1)
2、删除表中多余的重复记录,重复记录是根据单个字段(userCode)来判断,只留有rowid最小的记录
delete from
user
where
userCode
in
(select userCode from user group by userCode having count (peopleId) > 1)
and rowid not in
(select min(rowid) from user group by userCode having count(userCode)>1)
3、查找表中多余的重复记录(多个字段)
select
*
from
user a
where
(a.userCode,a.userName)
in
(select userCode,userName from user group by userCode,userName 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
user a
where
(a.userCode,a.userName)
in
(select userCode,userName from user group by userCode,userName having count(*) > 1)
and rowid not in
(select min(rowid) from user group by userCode,userName 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
user a
where
(a.userCode,a.userName)
in
(select userCode,userName from user group by userCode,userName having count(*) > 1)
and rowid not in
(select min(rowid) from user group by userCode,userName having count(*)>1)
推荐教程:《Oracle教程》
以上就是Oracle怎样查询重复字段的详细内容,转载自php中文网
发表评论 取消回复