我被困了几个星期，问题是我想让用户更容易地搜索到在取车和还车日期可用的汽车名称。这个查询是不正确的，我不知道要纠正它。
我有两张表：

Cars table:
carId (prim-key)
carType,
carName
carPrice

rent table:
rentId (prim-key)
rentStart date:
rentEnd date:
rentStatus,
rentCarId (foreign key) to carId in cars table.

到目前为止我已经能够实现搜索汽车名称了。
这是我代码

//model query builder
function search($car = null , $start, $end) {
      $start= $this->db->escape($start);
      $end= $this->db->escape($end);
      $this->db->select('  carId as id,
                           rentStatus as status,
                           rentStart as start,
                           rentEnd as end,
                           carName as name,
                           carType as type,
                           carPrice as price,
                           carImage as image
                        ');

      $this->db->from('cars');
      $this->db->group_by('carName');
      $this->db->join('rent', 'carId = rentCarId', 'left');
      $this->db->like('carName', $car);
      $this->db->where('rentEnd' > $start AND 'rentStart' < $end);
      $this->db->where('rentCarId', NULL);
      
      return $this->db->get()->result_array();
   }

//controller
public function search() {
   $start= $this->input->post('start');
   $end= $this->input->post('end');
   $car= $this->input->post('car');
   $id = $this->input->post('car-id');

   $data['cars'] = $this->M_cari->search($car, $start, $end);
    
   $this->template->title('Home');
   $this->template->build($this->module.'/v_search_index', $data);
}