刪除行的存儲過程 - SQL Server 2008 R2

Question

我已經編寫了一個存儲過程，只允許有100行，具有相同的CustomerPK，因此如果我們想要插入行101，需要刪除具有相同CustomerPK的最舊行。

我確信有幾種方法可以做到這一點，我不確定哪一個最好。這是程序的代碼。

DECLARE 
    @TokenCount INT; 

SELECT 
    @TokenCount = COUNT(*) 
FROM 
    CustomerAuthTokens 
WHERE 
    CustomerPK = @CustomerPK; 

IF @TokenCount > 99 
BEGIN 
    DELETE FROM CustomerAuthTokens 
    WHERE AuthToken IN (SELECT TOP(@TokenCount - 99) AuthToken 
         FROM CustomerAuthTokens 
         WHERE CustomerPK = @CustomerPK 
         ORDER BY TokenCreateTime ASC); 
END 

Answer 1

--Insert your row first 


-- This will delete customer rows if there are more than 100 rows for that customer 
;WITH cte as 
(
SELECT row_number() over (partition by CustomerPK order by TokenCreateTime desc) rn 
FROM CustomerAuthTokens 
WHERE CustomerPK = @CustomerPK 
) 
DELETE CTE 
WHERE rn > 100