SQL Server数据库删除数据集中重复数据实例讲解

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