oracle数据库数据量较大时更新数据较慢问题

merge into case_person_saxx t
using (select max(id) as id, app_id from case_xzcf group by app_id) s
on (t.app_id = s.app_id)
when matched then
  update set t.case_id = s.id;

  merge into invole_case_unit_saxx t
using (select max(id) as id, app_id from case_xzcf group by app_id) s
on (t.app_id = s.app_id)
when matched then
  update set t.case_id = s.id;

 

https://blog.csdn.net/u010402228/article/details/50155751