SQL存儲過程的問題

Question

我有以下存儲過程與發生

CREATE PROCEDURE LockRoots 
    -- Add the parameters for the stored procedure here 
    @lock uniqueidentifier, 
    @count int 
AS 
BEGIN 
    -- SET NOCOUNT ON added to prevent extra result sets from 
    -- interfering with SELECT statements. 
    SET NOCOUNT ON; 

    UPDATE R 
    SET R.[Lock] = @lock 
    FROM 
    (
     SELECT TOP @count * 
     FROM [Root] as R 
     --LEFT JOIN [Container] as C ON R.ID = C.RootID 
     WHERE [Lock] IS NULL 
     --ORDER BY NEWID() 
    ); 
END 
GO 

問題的問題「SELECT TOP @count *」，我爲什麼不能「選擇最前@VariableAmount」記錄？

Answer 1

Need parenthesis...

... 
SELECT TOP (@count) * 
... 

注：參數化TOP也SQL服務器2005+

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