删除SQL Server中的重复记录

Question

我编写了一个查询来删除表中的重复记录

;WITH a as
(
SELECT Firstname,ROW_NUMBER() OVER(PARTITION by Firstname, empID ORDER BY Firstname) 
AS duplicateRecCount
FROM dbo.tblEmployee
)
--Now Delete Duplicate Records
DELETE FROM tblEmployee
WHERE duplicateRecCount > 1 

但我不知道我说错了

列名无效 duplicateRecCount

有人能帮我吗？

Answer 1

您需要在删除语句中引用CTE ...

WITH a as
(
SELECT Firstname,ROW_NUMBER() OVER(PARTITION by Firstname, empID ORDER BY Firstname) 
AS duplicateRecCount
FROM dbo.tblEmployee
)
--Now Delete Duplicate Records
DELETE FROM a
WHERE duplicateRecCount > 1

Answer 2

 DELETE duplicates FROM
(SELECT ROW_NUMBER() OVER (PARTITION BY firstname, lastname, EMPNO, salary,dept  ORDER BY empno) cnt
 FROM tblEmp)  duplicates
WHERE duplicates.Cnt > 1