oracle删除重复行剩一条记录

[huizi_wo]

--删除重复的数据剩下一条，没有重复的数据就剩下
delete cncc_customeraddr_tab
where exists (select max(id)
from cncc_customeraddr_tab t
where t.ADDRSOURCETYPE = '1300000001'
group by t.arrearmain_id,
t.RELADDR,
t.addrsourcetype)

请帮我看看这个语句有什么问题，id为主键、

[rijing2000]

可以参考：http://www.help-doc.com/21/ShowPost.aspx

[heyixiang]

--删除重复的数据剩下一条，没有重复的数据就剩下
delete cncc_customeraddr_tab
where exists (select max(id)
from cncc_customeraddr_tab t
where t.ADDRSOURCETYPE = '1300000001'
group by t.arrearmain_id,
t.RELADDR,
t.addrsourcetype)

请帮我看看这个语句有什么问题，id为主键、




SQL> set feedback off;
SQL> create table cncc_customeraddr_tab
2 (
3 id number,
4 addrsourcetype varchar2(10),
5 arrearmain_id number,
6 reladdr varchar2(10)
7 );
SQL> insert into cncc_customeraddr_tab values (1,'1300000001',100,'a');
SQL> insert into cncc_customeraddr_tab values (2,'1300000001',100,'a');
SQL> insert into cncc_customeraddr_tab values (3,'1300000001',101,'b');
SQL> insert into cncc_customeraddr_tab values (4,'1300000001',102,'c');
SQL> insert into cncc_customeraddr_tab values (5,'1300000002',200,'a');
SQL> insert into cncc_customeraddr_tab values (6,'1300000002',201,'b');
SQL> insert into cncc_customeraddr_tab values (7,'1300000002',201,'b');
SQL> insert into cncc_customeraddr_tab values (8,'1300000002',201,'c');
SQL> insert into cncc_customeraddr_tab values (9,'1300000003',300,'a');
SQL> insert into cncc_customeraddr_tab values (10,'1300000003',300,'a');
SQL> insert into cncc_customeraddr_tab values (11,'1300000003',300,'b');
SQL> commit;
SQL> select * from cncc_customeraddr_tab;

ID ADDRSOURCETYPE ARREARMAIN_ID RELADDR
---------- -------------- ------------- ----------
1 1300000001 100 a
2 1300000001 100 a
3 1300000001 101 b
4 1300000001 102 c
5 1300000002 200 a
6 1300000002 201 b
7 1300000002 201 b
8 1300000002 201 c
9 1300000003 300 a
10 1300000003 300 a
11 1300000003 300 b

SQL> delete from cncc_customeraddr_tab
2 where id not in
3 (select max(id)
4 from cncc_customeraddr_tab
5 group by arrearmain_id, reladdr, addrsourcetype);
SQL> commit;
SQL> select * from cncc_customeraddr_tab;

ID ADDRSOURCETYPE ARREARMAIN_ID RELADDR
---------- -------------- ------------- ----------
2 1300000001 100 a
3 1300000001 101 b
4 1300000001 102 c
5 1300000002 200 a
7 1300000002 201 b
8 1300000002 201 c
10 1300000003 300 a
11 1300000003 300 b

SQL> drop table cncc_customeraddr_tab;
SQL>

[dawugui]

以下为sql server中写法,大多可以照用.

一张表里面以两个字段为唯一字段，当几条记录的这两个字段完全相同时，需要删除重复项，如下表
a b c d
1 2 3 4
1 5 3 5
1 2 7 9
以a、b为唯一字段，第一条和第三条的a、b完全相同，所以，需要删除第一条记录1 2 3 4 或者第三条记录1 2 7 9
即如下结果：
a b c d
1 2 3 4
1 5 3 5
或
a b c d
1 5 3 5
1 2 7 9

请问各位大侠这种sql语句怎么写


CREATE TABLE Tb1(id int, [a] varchar(255), [b] varchar(255), [c] varchar(255), [d] varchar(255))
INSERT Tb1(id, [a], [b], [c], [d])
SELECT 1, '1','2','3','4'
UNION ALL SELECT 2, '1','5','3','5'
UNION ALL SELECT 3, '1','2','7','9'
UNION ALL SELECT 4, '1','4','7','6'

delete Tb1 where [id] not in (select max([id]) from Tb1 group by a,b )
select * from tb1

drop table tb1

如果要同时删除第一和第三行
即如下结果：
a b c d
1 5 3 5

语句如下：

delete m from tb t
inner join
(
select a ,b
from tb
group by a , b
having count(*)>1
)n
on m.a = n.a and m.b = n.b
或
delete * from tb as m,
(
select a ,b
from tb
group by a , b
having count(*)>1
)n
where m.a = n.a and m.b = n.b








------------------------------------------------------------------------------------
在几千条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复的呢?谢谢!
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)

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
------------------------------------------------------------------------------------------------
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
set rowcount 0

方法二
　　有两个意义上的重复记录，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）
select * from tablename where id in (
select id from tablename
group by id
having count(id) > 1)

[HelloWorld_001]

delete cncc_customeraddr_tab - > delete from cncc_customeraddr_tab
where exists (select max(id) -> where not exists (select max(id)
from cncc_customeraddr_tab t
where t.ADDRSOURCETYPE = '1300000001'
group by t.arrearmain_id,
t.RELADDR,t.addrsourcetype)

[disturbed]

delete from cncc_customeraddr_tab a
where a.rowid> (select min(b.rowid)
from cncc_customeraddr_tab b
where b.ADDRSOURCETYPE='1300000001' )

[Slumber]

关键看什么字段相同算重复，如果是arrearmain_id、reladdr、addrsourcetype的话，那这样写是最高效的，因为用了rowid:
delete from cncc_customeraddr_tab t
where t.rowid > (select min(x.rowid)
from cncc_customeraddr_tab x
where x.arrearmain_id = t.arrearmain_id
and x.reladdr = t.reladdr
and x.addrsourcetype = t.addrsourcetype)
and t.addrsourcetype = '1300000001'

[hc_yao]

想回答个问题，都被人家回答了，唉
在Oracle里Slumber的方法是效率最高的。
此外要注意addrsourcetype要建索引，addrsourcetype的重复率比较高，候选值比较少，则arrearmain_id，reladdr和addrsourcetype也应该再建一个索引的。

[j2ee_fan]

楼主日死不厚道，别人回答那么多，也没说给点分，鄙视之！

[honglang_j]

dawugui
wonderful!

[编程小强]

学习了，谢谢