oracle判断查询结果是否为空

    declare
        cnta int;
    begin
        select count(*) into cnta from AS_SPJG where spid = :new.spid;
        if cnta = 0 then
            INSERT INTO AS_SPJG(SPID,
                                PRICE,
                                PRICE1,
                                REGION,
                                LASTTIME,
                                UP_STATUS)
            select :new.spid,
                   0,
                   0,
                   '',

                   to_char(sysdate, 'YYYY-MM-DD HH24:MI:SS'),
                   0

            FROM dual a;
        end if;
    end;

朋友们，请问还有其它的方法吗？ ，这么写也太费劲了