Convert the nesting mysql query into codeigniter s

Question

I have a nested sql query as below.

SELECT  A.ID, A.fName, A.lName,
   COALESCE (B.calls, 0) AS Calls
FROM TableA AS  A
   LEFT JOIN
   (
      SELECT COUNT(B.event) AS  Calls, B.ID
      FROM TableB AS B
      WHERE B.event LIKE 'call'
        AND `Time` >= 1360540800
        AND `Time` <= 1361232000
      GROUP BY B.ID

    ) B
      ON A.ID = B.ID 
WHERE A.State  LIKE 'SENT' OR A.State  LIKE 'SET'

I am trying to convert it in codeigniter style. I know Code Igniter's Active Record class does not natively support subqueries. But how could this be done. I have been trying the below code. So I made two different queries and combined them using union as below:

$query  = $this->db->query("select * from $subQuery2 UNION $subQuery1  as unionTable ");

Union is not the right way, can help me help me to convert it into codeigniter style.

Answer 1

You can use sub query way of codeigniter to do this for this purpose you will have to hack codeigniter. like this Go to system/database/DB_active_rec.php Remove public or protected keyword from these functions

public function _compile_select($select_override = FALSE)
public function _reset_select()

Now subquery writing in available And now here is your query with active record

$data   =   array(
                'COUNT(B.event) AS  Calls',
                'B.ID'
            );

$this->db
        ->select($data)
        ->from('TableB AS B')
        ->like('B.event','call','both')
        ->where('`Time` >=',1360540800)
        ->where('`Time` <=',1361232000)
        ->group_by('B.ID');

$subQuery = $this->db->_compile_select();
$this->db->_reset_select();
unset($data);
$data   =   array(
                'A.ID',
                'A.fName',
                'A.lName',
                'COALESCE (B.calls, 0) AS Calls'
            );
$this->db
        ->select($data)
        ->from('TableA AS A')
        ->join("$subquery")
        ->like('A.State','SENT','both')
        ->or_like('A.State','SET','both');

I have put both in the likes you can do according to your requirements. Note : While using sub queries you must use

$this->db->from('myTable')

instead of

$this->db->get('myTable')

which runs the query.