select * from
  curses curs
  LEFT OUTER JOIN
  (select * from users_curses where user_id=?)
  usCurs on curs.semester_id = usCurs.semester_id and curs.curse_id = usCurs.curse_id where curs.subject_id = ? and curs.semester_id = ?;

select item.idItem,costing.dateCost
from Item item left join(select * from Costing where std_01 <='12') costing
on item.idItem=costing.idItem;

select item.idItem,costing.dateCost
from Item  as item left join(select costing.std01 from
     Costing where costing.std01 <='12') as costing