SQL存储过程问题

Question

我有一个问题，涉及以下存储过程

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

问题出现在 "SELECT TOP @count *" 语句上，为什么我不能选择 @VariableAmount 条记录？

- Lu4

---

可能是重复的问题：如何从表中获取前n行，其中n的值在运行时传递？ - David Hall

Answer 1

Need parenthesis...

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

注意：对于参数化TOP，还需要SQL Server 2005及以上版本。

- gbn