SQL Server数据库删除数据集中重复数据实例讲解

sql server数据库操作中，有时对于表中的结果集，满足一定规则我们则认为是重复数据，而这些重复数据需要删除。如何删除呢？本文我们通过一个例子来加以说明。

例子如下：

如下只要companyname,invoicenumber,customernumber三者都相同，我们则认为是重复数据，下面的例子演示了如何删除。

declare @invoicelistmaster table ( id int identity primary key ,  
 
companyname nchar(20),  
 
invoicenumber int,  
 
customernumber int,  
 
rmanumber int )  
 
insert  @invoicelistmaster  
 
select n'华为', 1001,100,200  
 
union all  
 
select n'华为', 1001,100,300  
 
union all  
 
select n'华为', 1001,100,301  
 
union all  
 
select n'中兴', 1002, 200,1     
 
union all  
 
select n'中兴', 1002, 200,2  
 
select * from @invoicelistmaster  
 
delete a  
 
from (  
 
select rown = row_number( )over( partition by companyname,  
 
invoicenumber,  
 
customernumber   
 
order by companyname,  
 
invoicenumber,  
 
customernumber ),  
 
companyname,  
 
invoicenumber,  
 
customernumber  
 
from @invoicelistmaster )a  
 
where exists ( select 1   
 
from ( select rown = row_number( )over( partition by companyname,  
 
invoicenumber,  
 
customernumber   
 
order by companyname,  
 
invoicenumber,  
 
customernumber ),  
 
companyname,  
 
invoicenumber,  
 
customernumber  
 
from @invoicelistmaster ) b  
 
where b.companyname = a.companyname  
 
and b.invoicenumber = a.invoicenumber  
 
and b.customernumber = a.customernumber  
 
and a.rown > b.rown  
 
)  
 
select * from @invoicelistmaster 

以上的例子就演示了sql server数据库删除数据集中重复数据的过程，希望本次的介绍能够对您有所收获！