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！
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