update-piratees

gistfile1.txt

update piratees p
  join (     
    select p1.id, min(ps.ship_in) as ship_in
      from piratees p1
      join piratee_login ps on ps.piratee_id = p1.id
     where ps.ship_in is not null 
       and ps.ship_in != '0000-00-00 00:00:00'
     group by p1.id
  ) as ps
  on ps.id = p.id
  set p.start_date = ps.ship_in
  where p.start_date = '0000-00-00'