<?php

class GroupByCriterion
{

    private $first;
    private $second;

    private function __construct($first, $second)
    {
        $this->first = $first;
        $this->second = $second;
    }

    private static function sinit()
    {
        self::$COMPANY_ANSWERS = new GroupByCriterion('company_id', 'answer_id');
    }

    public static $COMPANY_ANSWERS;
}

GroupByCriterion::sinit();