SQL Server數據庫刪除數據集中重復數據實例講解

SQL Server數據庫操作中，有時對於表中的結果集，滿足一定規則我們則認為是重復數據，而這些重復數據需要刪除。如何刪除呢？本文我們通過一個例子來加以說明。

例子如下：

如下只要companyName,invoiceNumber,customerNumber三者都相同，我們則認為是重復數據，下面的例子演示了如何刪除。

declare @InvoiceListMaster table ( ID int identity primary key ,  
 
companyName Nchar(20),  
 
invoiceNumber int,  
 
CustomerNumber int,  
 
rmaNumber int )  
 
insert  @InvoiceListMaster  
 
select N'華為', 1001,100,200  
 
union all  
 
select N'華為', 1001,100,300  
 
union all  
 
select N'華為', 1001,100,301  
 
union all  
 
select N'中興', 1002, 200,1     
 
union all  
 
select N'中興', 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數據庫刪除數據集中重復數據的過程，希望本次的介紹能夠對您有所收獲！