么么茶的SQL問題.该如何解决

么么茶的SQL問題.
DECLARE @output_a numeric(9,0) 
DECLARE @cmd nvarchar(200) 
SET @cmd= 'SELECT TOP 1 @a=mbrefid FROM reply ORDER BY leavewordtime ' 
EXEC SP_EXECUTESQL @cmd,N'@a numeric(9,0) OUTPUT',@a=@output_a OUTPUT
select @output_a as TestField
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這樣試試.
帖子刪除掉了?

------解决方案--------------------------------------------------------
把这句改一下。 
EXEC SP_EXECUTESQL @cmd,N '@a numeric(9,0) OUTPUT ',@a=@output_a OUTPUT 

改为：

EXEC SP_EXECUTESQL @cmd,N '@a numeric(9,0) OUTPUT ',@output_a OUTPUT