案例讨论：Oracle数据库的分组问题

　　with r as {　　select CLM001 ,sum(score) as total from b group by CLM001　　}　　update a set score = (select total from r where r.CLM001 =a.CLM001)　　where exists (select 1 from r where r.CLM001 =a.CLM001)

　　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;

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