procedure a(
                    in_accno      in  varchar2,
                    ret_code      out number,
                    ret_errmsg    out varchar2
                      )
as
v_ncount number:=0;
v_accno  varchar(100);begin    
    v_accno:=trim(in_accno);    SELECT  count(*)
        into v_ncount
        from b
        where accno=v_accno
        ;    if v_ncount=0 then
        begin
            ret_code:=1;
            return;
        end;
    elsif v_ncount = 1 then
        begin
             select * from c;
        end;
    else
        begin
            ret_code:=2;
            return;
        end;
    end if;
end;
存储过程如上,请问if里的begin/end不用行不行,用的意义是什么?谢谢!