What the best way to deal with codeigniter php array_merge, in a foreach?

Question

What is the best way to deal with php array_merge, in a foreach

Answer 1

$school_students is being overwritten for every pass of your foreach-loop. One alternative is to simply add the results to an array like so:

    foreach($schools as $row):
            $school_db_name    =   $row['school_db_name'];
            $this->db->query("use $school_db_name");
            $school_students[]    =   $this->db->select('*')
                                    ->from('school_students')
                                    ->get()->result_array();
    endforeach;

If you need to flatten the array afterwards you can for example use this:

$recipients = array_merge(...$school_students)