在存储过程中的查询delphi怎么出错

REATE procedure employee_select  @cust_num varchar(20),@ErrMsg varchar(100) out
as
            select @ErrMsg = ''
      if ((@cust_num is null ) or (@cust_num = ''))
        begin
select a.cust_num,a.cust_name,a.sex,b.sbname as custkindname,a.opername,a.opertime ,
(select c.sbname from dictionary c where c.type_id=2  and c.hold1 = a.custkind_id and c.serial_id = a.rating_id ) as cust,a.up_opername
from employee a ,dictionary b where type_id=1 and b.serial_id=a.custkind_id
return 0
end
if not exists(select * from employee where cust_num=@cust_num)
        begin
Set @ErrMsg='当前['+@cust_num+']信息不存在'
      Return -1

end
else
 
          begin
select a.cust_num,a.cust_name,a.sex,b.sbname as custkindname,a.opername,a.opertime ,
(select c.sbname from dictionary c where c.type_id=2  and c.hold1 = a.custkind_id and c.serial_id = a.rating_id ) as cust,a.up_opername
from employee a ,dictionary b where type_id=1 and b.serial_id=a.custkind_id and a.cust_num=@cust_num
  end
 
  return 0
GO
这是我的存储过程
在查询分析器里面房上参数有结果返回，
下面是在delphi的代码： <