SQL Server数据库如何删除数据集中重复的数据？
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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