sql 错误???

Question

ALTER PROCEDURE punish_outtime1
    (
        @p_man varchar(50),
        @comparetime varchar(50),
        @outtime int output
    )
AS
    
    select @outtime=count(*) from
    (
    select top 1 *
    from punish 
    where p_man=@p_man 
    and datediff(day,p_begintime,@comparetime)<=60
    )<-----提示这个")"附近有语法错误
----------------------------------------
改成这样就不会错....什么问题?大家帮帮
ALTER PROCEDURE punish_outtime1
    (
        @p_man varchar(50),
        @comparetime varchar(50)
    )
AS    select top 1 *
    from punish 
    where p_man=@p_man 
    and datediff(day,p_begintime,@comparetime)<=60

Answer 1

ALTER PROCEDURE punish_outtime1
    (
        @p_man varchar(50),
        @comparetime varchar(50),
        @outtime int output
    )
AS
    
    select @outtime=count(*) 
from
     ( select top 1 *
       from punish 
      where p_man=@p_man 
        and datediff(day,p_begintime,@comparetime)<=60
     ) as aa

Answer 2

能解析下为什么要加 as aa 吗?