oracle查找重复记录-转

SELECT *
FROM t_info a
WHERE ((SELECT COUNT(*)
FROM t_info
WHERE Title = a.Title) > 1)
ORDER BY Title DESC

一。查找重复记录

1。查找全部重复记录

Select * From 表 Where 重复字段 In (Select 重复字段 From 表 Group By 重复字段 Having Count(*)>1)

2。过滤重复记录(只显示一条)

Select * From HZT Where ID In (Select Max(ID) From HZT Group By Title)

注：此处显示ID最大一条记录

二。删除重复记录

1。删除全部重复记录（慎用）

Delete 表 Where 重复字段 In (Select 重复字段 From 表 Group By 重复字段 Having Count(*)>1)

2。保留一条（这个应该是大多数人所需要的 ^_^）

Delete HZT Where ID Not In (Select Max(ID) From HZT Group By Title)

注：此处保留ID最大一条记录

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(*)>1)

补充：

有两个以上的重复记录，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

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

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

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）

时间： 2024-09-28 00:45:09

oracle查找重复记录-转的相关文章

oracle查找重复记录

SELECT *FROM t_info aWHERE ((SELECT COUNT(*) FROM t_info WHERE Title = a.Title) > 1)ORDER BY Title DESC 一.查找重复记录 1.查找全部重复记录 Select * From 表 Where 重复字段 In (Select 重复字段 From 表 Group By 重复字段 Having Count(*)>1) 2.过滤重复记录(只显示一条) Select *

初探oracle删除重复记录，只保留rowid最小的记录

如题,初探oracle删除重复记录,只保留rowid最小的记录(rowid可以反映数据插入到数据库中的顺序) 一.删除重复记录可以使用多种方法,如下只是介绍了两种方法(exist和in两种). 1.首先创建一个测试表. create table my_users( id number, username varchar2(20), sal number ) 2.插入测试数据 begin for i in 1..10 loop insert into my_users values(i,'carl

查找重复记录（GROUP BY goods_name HAVING count(goods_name) >= 2;）

//查找重复记录 SELECT * FROM 表 GROUP BY goods_name HAVING count(goods_name) >= 2;

oracle去掉重复记录语句

比如现在有一人员表 (表名:peosons) 若想将姓名.身份证号.住址这三个字段完全相同的记录查询出来 select p1.* from persons p1,persons p2 where p1.id<>p2.id and p1.cardid = p2.cardid and p1.pname = p2.pname and p1.address = p2.address 可以实现上述效果． www.2cto.com 几个删除重复记录的SQL语句 1.用rowid方法 2.用group

SQL 查找重复记录

CREATE TABLE product( ID INT IDENTITY(1,1) PRIMARY KEY NOT NULL, Pid INT NOT NULL, Pname VARCHAR(50) NOT NULL, Punit CHAR(10) NOT NULL, Pspec VARCHAR(50), PbarCode VARCHAR(20),) INSERT INTO product(Pid,Pname,Punit,Pspec,PbarCode) VALUES(10000,'欧莱雅日间修

SQL Server 数据库查找重复记录的几种方法

http://www.hanyu123.cn/html/c61/6790.html 一.查某一列(或多列)的重复值.(只可以查出重复记录的值,不能查出整个记录的信息) 例如:查找stuid,stuname重复的记录: select stuid,stuname from stuinfo group by stuid,stuname having(count(*))>1 二.查某一列有重复值的记录.(此方法查出的是所有重复的记录,如果有两条记录重复的,就查出两条) 例如:查找stuid重复的记录:

【转】oracle 删除重复记录

转至:http://blog.163.com/aner_rui/blog/static/12131232820105901451809/ 2.保留一条(这个应该是大多数人所需要的 ^_^) Delete HZT Where ID Not In (Select Max(ID) From HZT Group By Title) 注:此处保留ID最大一条记录 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 people

oracle删除重复记录，只保留一条

表 create table AA_TEST ( aaaa NVARCHAR2(20), bbbb NUMBER, cccc NVARCHAR2(20) ) 删除分两步:先保存满足要求的 delete from aa_test t where (t.aaaa,t.bbbb) not in ( select t1.aaaa,max(t1.bbbb) from aa_test t1 group by t1.aaaa ); 第二步再在第一步基础上删去重复记录 delete from aa_

mysql 数据表中查找重复记录

//例一:select name1,count(*) as count from table_name group by name1 having count>1;//例二:select name1,name2 ,count(name1) as countb,count(name2) as count from table_name group by name1,name2 having count>1 and countb >1;