Question

I have a form on which I have a multiselect for different boxes and for boxes there exists some records i-e (the number of openings of the box) in the database but it might be possible that for a selected box no records exists ie (the box is not opened even single time). Currently when I select different boxes and if records does not exist for a box it does not return the empty array for that box I want to it return even the empty results for the selected box. My query is

public function getBoxOpenings($boxes, $from_date, $to_date){
$query = $this->db->select('box_id, COUNT(box_id) AS Openings')
    ->from('boxes')
    ->where_in('box_id', $boxes)
    ->where('actiontime >=', $from_date)
    ->where('actiontime <=', $to_date)
    ->group_by('box_id')
    ->get();
$data = $query->result_array();
return $data;
}

If I select 3 boxes and submit the form and records exists for only 2 boxes it returns something like this

 Array
(
[0] => Array
    (
        [mc_boxes_idmc_boxes] => 12
        [location] => FRA-Air
        [Openings] => 1
    )

[1] => Array
    (
        [mc_boxes_idmc_boxes] => 14
        [location] => FRA-Hof
        [Openings] => 1
    )

)

How can I get all three records with one empty like this

[2] => Array
    (
        [mc_boxes_idmc_boxes] => 16
        [location] => Test
        [Openings] => 
    )

How Can I get the records for all the selected boxes with empty arrays for those which have no records.

Thanks

Answer 1

The problem here is obvious: You only insert a row into that table when the box is opened by user. If the box not opened ever that table contains no record for that box.

If You then do a select * from table where id in (1, 2, 3, 4, 5) but Your table contains only rows for ids 2 and 3, the result set will contain only the data for the ids 2 and 3 as there are no records found for other ids.

I guess You only could call this query in a loop for each $box_id from $boxes – when the data is found return it otherwise return zero. Like this:

public function getBoxOpenings($boxes, $from_date, $to_date){
    $data = array();
    foreach($boxes as $box) {
        $query = $this->db->select('box_id, COUNT(box_id) AS Openings')
            ->from('boxes')
            ->where('box_id = ', $box)
            ->where('actiontime >= ', $from_date)
            ->where('actiontime <= ', $to_date)
            ->group_by('box_id')
            ->get();
        $res = $query->result_array();
        if($res)
            $data[] = $res;
        else
            $data[] = array('box_id' => $box, 'Openings' => 0);
    }
    return $data;
}

But this is not very nice as You do one query per each box that will be very resource consuming when having a lot of boxes…