查询同一表内多字段同时重复记录的SQL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．   
 
几个删除重复记录的SQL语句  
 
1.用rowid方法   
 
2.用group by方法   
 
3.用distinct方法   
 
 
1。用rowid方法   
 
据据Oracle带的rowid属性，进行判断，是否存在重复,语句如下：  
查数据:  
select * from table1 a where rowid !=(select max(rowid)   
from table1 b where a.name1=b.name1 and a.name2=b.name2......)  
删数据：  
delete from table1 a where rowid !=(select max(rowid)   
from table1 b where a.name1=b.name1 and a.name2=b.name2......)   
 
2.group by方法   
 
查数据:  
select count(num), max(name) from student --列出重复的记录数，并列出他的name属性   
group by num   
having count(num) >1 --按num分组后找出表中num列重复，即出现次数大于一次   
删数据：  
delete from student   
group by num   
having count(num) >1  
这样的话就把所有重复的都删除了。   
 
3.用distinct方法 -对于小的表比较有用   
 
create table table_new as select distinct * from table1 minux   
truncate table table1;  
insert into table1 select * from table_new;  
 
 
 
查询及删除重复记录的方法大全  
 
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)  
 
 
(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 
end 
close cur_rows  
set rowcount 0  
 
 
方法二  
＂重复记录＂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）   
 
 
(四)  
查询重复  
select * from tablename where id in (  
select id from tablename   
group by id   
having count(id) > 1  
)