删除重复记录

大家平日在数据库中有双重的记录那时大家盼望删除那几个重复的记录
你不要告诉笔者你是一条条手动删除的哈:
selectdistinct*intonewtableformtablename droptabletablename
select*intotablefromnewtable droptablenewtable 思路好了就好做.

select * from vitae a where (a.tableId,a.seq) in (select tableId,seq from vitae group by tableId,seq having count(*)  1)

3、查找表中多余的重复记录

6、查询出二个表中,某一列的值是同一的SQL:

delete 表名 from 表名 as Twhereexists( select 1from表名 where 字段A=T.字段A and 字段B=T.字段B,(....) and自增列  T.自增列)

3、查找表中多余的重复记录

三,查询并剔除重复记录的SQL语句

方法一

即使还查性别也一模一样大则如下:

select * from 表 where Id in (select Id from 表 group byId having count(Id)  1)
select * from vitae a where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*)  1) 
delete from 表名 a where 字段1,字段2 in (select 字段1,字段2 from 临时表);

2、那类重复难题平日要求保留重复记录中的第一条记下,操作方法如下
倘使有重复的字段为Name,Address,需要赢得那四个字段独一的结果集

上面就足以开展如此的删除操作了:

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) 

2、删除表中多余的重复记录,重复记录是依照单个字段来判别,只留有rowid最小的笔录。

(二卡塔尔 譬如说 在A表中留存二个字段“name”,
况且区别记录之间的“name”值有异常的大或者会周边,
以后正是内需查询出在该表中的各记录之间,“name”值存在重新的项;

由此,大家要去除重复数据,只保留最新的一条数据,就能够如此写了:

一、查询有个别字段重复

select * from 表 a where (a.Id,a.seq) in(select Id,seq from 表 group by Id,seq having count(*)  1)

结果

select * from peoplewhere peopleId in  1)
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) 

删数据:

注:rowid为oracle自带不用该…..

select * from vitae awhere in  1)

2、删除表中多余的重复记录,重复记录是依附单个字段来推断,只留有rowid最小的笔录

一张person表,有id和name的多少个字段,id是独一的不容许再一次,id相似则以为是重复的笔录。

(三)

select distinct * into #Tmp from tableNamedrop table tableNameselect * into tableName from #Tmpdrop table #Tmp

方法一

SELECT TEST_NAME,COUNT(*) FROM T_TEST GROUP BY TEST_NAME HAVING COUNT(*)  1

终极三个select即得到了Name,Address不另行的结果集

delete from 表名 a where a.rowid != (select max(b.rowid) from 表名 b where a.字段1 = b.字段1 and a.字段2 = b.字段2 )

测验情状

select 字段1,字段2,count(*) from 表名 group by 字段1,字段2 having count(*)  1

set rowcount 0 方法二
"重复记录"有七个意思上的重复记录,一是一丝一毫重复的记录,也即怀有字段均再一次的记录,二是部分主要字段重复的笔录,举个例子Name字段重复,而此外字段不必然再一次或都重复能够忽视。
1、对于第一种重复,相比便于消释,使用 select distinct * from tableName
就足以得到无重复记录的结果集。
假诺该表要求删除重复的记录,能够按以下办法删除

Oracle删除重复数据的SQL:

(四State of Qatar 查询重复

举例说在A表中留存三个字段“name”,而且分歧记录之间的“name”值有望会相像,今后正是内需查询出在该表中的各记录之间,“name”值存在重新的项;

5、查找表中剩下的重复记录,不分包rowid最小的笔录

4、删除表中多余的重复记录,只留有rowid最小的笔录

create table TableA ( id varchar(3),customer varchar(5),PhoneNo varchar(6)) insert into TableA select '001','张三','777777' union all select '002','李四','444444' union all select '003','王五','555555' union all select '004','张三','777777' union all select '005','张三','777777' union all select '006','王五','555555'
Select Name,Count From A Group By Name Having Count  1
 select * from User u where u.user_name in (select u.user_name from User u group by u.user_name having count(*)  1)

一经还查性别也同等大则如下:

该措施适用于有叁个字段为自增性,举例本例中的:id

delete from peoplewhere peopleId in  1)and rowid not in from people group by peopleId having count1)

二,删除表中某多少个字段的双重

去除重复数据

select * from people where peopleId in (select peopleId from people group by peopleId having count(peopleId)  1) 

一、背景

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)

建议先将查询到的重复的多少插入到三个有的时候表中,然后对实行删减,那样,实施删除的时候就无须再开展一次询问了。如下:

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 end close cur_rows 

二、解决

select distinct * into #Tmp from tableName drop table tableName select * into tableName from #Tmp drop table #Tmp 

比方说现在有一个人石英手表若想将人名、居民身份证号、住址那八个字段完全相像的记录查询出来

4、删除表中多余的重复记录,只留有rowid最小的记录

delete from vitae a where (a.tableId,a.seq) in (select tableId,seq from vitae group by tableId,seq having count(*)  1)and rowid not in (select min(rowid) from vitae group by tableId,seq having count(*)1)
select * from tablename where id in ( select id from tablename group by id having count(id)  1 )

4、删除表中多余的重复记录,只留有rowid最小的记录

Select Name,Count(*) From A Group By Name Having Count(*)  1 

剔除重复数据

Select Name,sex,Count(*) From A Group By Name,sex Having Count(*)  1 

3、查找表中多余的重复记录

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,重复记录是依据单个字段来判别

前天正是内需查询出在该表中的各记录之间,“name”值存在重复的项;

id customer PhoneNo 001 张三 777777 002 李四 444444 003 王五 555555 004 张三 777777 005 张三 777777 006 王五 555555 如何写一个sql语句将TableA变成如下 001 张三 777777 002 李四 444444 003 王五 555555