Question

我需要查找FIRSTNAME是重复且LASTNAME是重复的所有记录

所以我的数据有点像这样：

FirstName    LastName    CustomerFileLocation    
   Joe        Smith         c:\file1     
   Joe        Jones         c:\File2     
   Joe        Smith         c:\File3     
   Harry      Smith         c:\File4

我希望查询返回

Joe      Smith      c:\file1
Joe      Smith      c:\File3

我写了这个来选择它们，但如果我将CustomerFileLocation添加到GROUP BY表达式，它就不会返回任何内容。

SELECT        FirstName, LastName, COUNT(1) AS CNT, CustomerFileLocation
FROM            tblCustomerList
WHERE        (Skip = 0)
GROUP BY FirstName, LastName
HAVING        (COUNT(1) > 1)

Answer 1

SELECT (FirstName + ' ' + LastName) as fullname, 
       cast(CustomerFileLocation as nvarchar) as location 
FROM tblCustomerList WHERE (Skip = 0) GROUP BY  (FirstName + ' ' + LastName), 
cast(customerFileLication as nvarchar) having count(1)>1

我还没有对其性能进行测试或调整，但这条线必须有效。

Answer 2

您可以尝试使用子查询返回包含任何计数大于1的记录的表，然后将该表连接回该子查询。

没有尝试过，但它看起来像这样。

SELECT tblCustomerList.FirstName, tblCustomerList.LastName, tblCustomerList.CustomerFileLocation From (SELECT FirstName, LastName, COUNT(1) AS CNT, CustomerFileLocation
FROM tblCustomerList
WHERE
GROUP BY FirstName, LastName
HAVING (COUNT(1) > 1))) as countTable inner join tblCustomerList 
on countTable.lastname = tblCustomerList.lastname and countTable.firstname = tblCustomerList.firstname and tblCustomerList.Skip = 0

检查重复项时如何返回列？

2 个答案: