oracle多結果集嵌套循環處理優化

--性能差
begin
 for a in (select id,name,sex,idcard from people) loop
    for b in (select id,name,sex,idcard from english) loop
       if a.idcard = b.idcard then
       --do something
       end if;
    end loop;
 end loop;
end;

--性能優：將多表合並成一個結果集，避免嵌套循環
begin
 for a in (select
 
 p.id,p.name,p.sex,p.idcard from people p,english e where p.idcard = e.idcard) loop
       --do something
 end loop;
end;

oracle PLSQL 多結果集嵌套循環處理優化