exists 之后追加怎么写？？？

Question

select * from VIEW_TBP_CONTACTSINGLEOPERAT  where exists(select * from view_tbs_user_project t2 where t2.user_account='admin1' and t2.project_id=VIEW_TBP_CONTACTSINGLEOPERAT.project_id) ORDER BY CONTACT_ID DESC
执行完上面的语句我想在加入where project_id is null 
请问高手怎么写啊 ？？？？

Answer 1

select *
  from VIEW_TBP_CONTACTSINGLEOPERAT
 where project_id is null
   and exists
 (select *
          from view_tbs_user_project t2
         where t2.user_account = 'admin1'
           and t2.project_id = VIEW_TBP_CONTACTSINGLEOPERAT.project_id)
 ORDER BY CONTACT_ID DESC

Answer 2

select * from VIEW_TBP_CONTACTSINGLEOPERAT where exists(select * from view_tbs_user_project t2 where t2.user_account='admin1' and t2.project_id=VIEW_TBP_CONTACTSINGLEOPERAT.project_id) and project_id is null  ORDER BY CONTACT_ID DESC

Answer 3

好像要用OR用AND 查不到结果