sqlserver 存储过程的新建与执行

if Exists(select * from sysobjects where NAME = 'insert_custominfo' and type='P')
    drop procedure insert_custominfo
go
create proc insert_custominfo
@mid nvarchar(50),
@custominfoid nvarchar(50) output
as
begin
declare @num int
  set @num =(  select COUNT(*) from t_custominfo where c_id=@mid )
  if(@num =0)
     begin
        insert into  t_custominfo(c_id) values(@mid)
        set @custominfoid = @@IDENTITY
    end
  else
    begin
         select @custominfoid=c_custominfoid from t_custominfo where c_id=@mid
    end
end

declare @custominfoid int
 exec insert_custominfo '',@custominfoid output
     print @custominfoid