在CodeIgniter中对WHERE子句进行分组

Question

I have a query like this.

WHERE (timetable_id = '1' 
       OR timetable_id = '2' 
       OR timetable_id = '3' 
       OR timetable_id = '4' 
       OR timetable_id = '5' 
       OR timetable_id = '6')

AND exam_name_id = '5'

But I don't know how to execute this in Codeigniter.

I have tried this

while(@$i <= 6 {                         
   $this->db->or_where('timetable_id',$this->input->post('timetable_id'.$i));
   $i++;   
   }                    
$this->db->where('et.exam_name_id',5); 

But the above command gives output like this

WHERE timetable_id = '1'
      OR timetable_id = '2' 
      OR timetable_id = '3' 
      OR timetable_id = '4' 
      OR timetable_id = '5' 
      OR timetable_id = '6'
      AND et.exam_name_id = '5'

This gives all the outputs. How to do that correctly? Please Note in my query I have () braces.

Answer 1

@$i = 1;
$n = $this->input->post('timetable_id'.$i);
$or_where = "(";
$or_where.="timetable_id = $n";
for ($i; $i <= 6; $i++) {
    $n = $this->input->post('timetable_id'.$i);
    $or_where.=" OR timetable_id = $n";
}
$or_where.=")";     
$this->db->or_where($or_where);

This will give your expected answer.