案例讨论：Oracle数据库的分组问题

　　create or replace procedure p_test

　　as

　　v_clm001 a.clm001%type;

　　cursor c_record is

　　select distinct clm001 from b;

　　begin

　　open c_record;

　　loop

　　fetch c_record into v_clm001;

　　exit when c_record%notfound;

　　update a set score =(select sum(score) from b where clm001=v_clm001)

　　where clm001=v_clm001;

　　end loop;

　　end;

　　(select CLM001,sum(score) from b group by CLM001) b where a.CLM001 = b.CLM001)