$list2 = M('property')
->alias('p')
->field(['p.id', 'p.name','p.num','d.name as department_name','t.name as
area_name'])
->join('left join department As d ON p.did=d.id')
->join('left join training_room As t ON p.cid=t.id')
->where($condition)
->select();