查询一个表中存在一列相同一列不相同的数据&查询删除重复数据

=========查询一个表中存在一列相同一列不相同

SELECT  T1.plucode,T1.pluid,t1.iscansale

FROM tposgtplu  T1

JOIN tposgtplu  T2 ON T1.plucode = T2.plucode AND T1.pluid <> T2.pluid

 

=================统计

select  distinct plucode,pluid,iscansale from (

SELECT  T1.plucode,T1.pluid,t1.iscansale

FROM tskugtplu  T1

JOIN tskugtplu  T2 ON T1.plucode = T2.plucode AND T1.pluid <> T2.pluid) order by plucode

 

==================查询重复记录说明

select * from tablename where 重复字bai段1 in (select 重复字段1 from tablename group by 重复字段1,重复字段2 having count(*)>1)。

SQL重复记录du查询方法：zhi

1、查找表中多余的重复记录，dao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

 

==============================

 

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,seqhaving count(*) > 1)

and rowid not in (select min(rowid) from vitae group by peopleId,seq havingcount(*)>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,seqhaving count(*) > 1)

and rowid not in (select min(rowid) from vitae group by peopleId,seq havingcount(*)>1) 

(二)

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

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，使用以下语句就可以得到无重复记录的结果集。

select distinct * from tableName 

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 

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

)