Подготовленный оператор PHP с переменной сеанса MySQL

В настоящее время у меня есть запрос ниже, который использует соединение UNION для соединения двух запросов и переменных SQL для чередования порядка отображения строк между суммой чисел и количеством действий. Когда я добавляю строки SET в запрос, в файле PHP появляется ошибка, и когда я их удаляю, запрос выполняется, но значения не извлекаются. Я запустил запрос на сервере, и он работает.

Как использовать переменные SQL в подготовленном операторе? Если это невозможно, как бы я переписал запрос, чтобы получить тот же результат?

SET @a = 0;
SET @b = 0;
SELECT * FROM(
    SELECT @a := @a + 1 AS sortOne, 1 AS sortTwo, tbl_company.comp_name AS comp_name, tbl_shift.shift_name AS shift_name,
                          SUM(tbl_short_term_programme.sun_p) AS sun_p_total, SUM(tbl_short_term_programme.sun_a) AS sun_a_total,
                          SUM(tbl_short_term_programme.mon_p) AS mon_p_total, SUM(tbl_short_term_programme.mon_a) AS mon_a_total,
                          SUM(tbl_short_term_programme.tue_p) AS tue_p_total, SUM(tbl_short_term_programme.tue_a) AS tue_a_total,
                          SUM(tbl_short_term_programme.wed_p) AS wed_p_total, SUM(tbl_short_term_programme.wed_a) AS wed_a_total,
                          SUM(tbl_short_term_programme.thu_p) AS thu_p_total, SUM(tbl_short_term_programme.thu_a) AS thu_a_total,
                          SUM(tbl_short_term_programme.fri_p) AS fri_p_total, SUM(tbl_short_term_programme.fri_a) AS fri_a_total,
                          SUM(tbl_short_term_programme.sat_p) AS sat_p_total, SUM(tbl_short_term_programme.sat_a) AS sat_a_total
                        FROM tbl_short_term_programme
                          INNER JOIN tbl_phase ON tbl_short_term_programme.phase_id = tbl_phase.phase_id
                          INNER JOIN tbl_company ON tbl_short_term_programme.company_id = tbl_company.company_id
                          INNER JOIN tbl_shift ON tbl_short_term_programme.shift_id = tbl_shift.shift_id
                        WHERE tbl_phase.phase_hash = ? AND YEARWEEK(tbl_short_term_programme.short_term_date, 2) = YEARWEEK(?, 2)
                        GROUP BY tbl_shift.shift_id, tbl_company.comp_name 
    UNION                             
    SELECT @b := @b + 1 AS sortOne, 2 AS sortTwo, tbl_company.comp_name AS comp_name, tbl_shift.shift_name AS shift_name,
                          COUNT(tbl_short_term_programme.sun_p) AS sun_p_total, COUNT(tbl_short_term_programme.sun_a) AS sun_a_total,
                          COUNT(tbl_short_term_programme.mon_p) AS mon_p_total, COUNT(tbl_short_term_programme.mon_a) AS mon_a_total,
                          COUNT(tbl_short_term_programme.tue_p) AS tue_p_total, COUNT(tbl_short_term_programme.tue_a) AS tue_a_total,
                          COUNT(tbl_short_term_programme.wed_p) AS wed_p_total, COUNT(tbl_short_term_programme.wed_a) AS wed_a_total,
                          COUNT(tbl_short_term_programme.thu_p) AS thu_p_total, COUNT(tbl_short_term_programme.thu_a) AS thu_a_total,
                          COUNT(tbl_short_term_programme.fri_p) AS fri_p_total, COUNT(tbl_short_term_programme.fri_a) AS fri_a_total,
                          COUNT(tbl_short_term_programme.sat_p) AS sat_p_total, COUNT(tbl_short_term_programme.sat_a) AS sat_a_total
                        FROM tbl_short_term_programme
                          INNER JOIN tbl_phase ON tbl_short_term_programme.phase_id = tbl_phase.phase_id
                          INNER JOIN tbl_company ON tbl_short_term_programme.company_id = tbl_company.company_id
                          INNER JOIN tbl_shift ON tbl_short_term_programme.shift_id = tbl_shift.shift_id
                        WHERE tbl_phase.phase_hash = ? AND YEARWEEK(tbl_short_term_programme.short_term_date, 2) = YEARWEEK(?, 2)
                        GROUP BY tbl_shift.shift_id, tbl_company.comp_name
) AS result ORDER BY sortOne, sortTwo
    $stmt->bind_param("ssss", $phase_hash, $formatted_date, $phase_hash, $formatted_date);
    $stmt->execute();
    $stmt->store_result();
    $stmt->bind_result($comp_name, $shift_name, $sun_p_total, $sun_a_total, $mon_p_total, $mon_a_total, $tue_p_total,
                    $tue_a_total, $wed_p_total, $wed_a_total, $thu_p_total, $thu_a_total, $fri_p_total, $fri_a_total,
                    $sat_p_total, $sat_a_total);
    $row_array = array();

    while($stmt->fetch()) {
        $tmp = array();
        $tmp["shift_name"] = $shift_name;
        $tmp["comp_name"] = $comp_name;
        $tmp["sun_p_total"] = $sun_p_total;
        $tmp["sun_a_total"] = $sun_a_total;
        $tmp["mon_p_total"] = $mon_p_total;
        $tmp["mon_a_total"] = $mon_a_total;
        $tmp["tue_p_total"] = $tue_p_total;
        $tmp["tue_a_total"] = $tue_a_total;
        $tmp["wed_p_total"] = $wed_p_total;
        $tmp["wed_a_total"] = $wed_a_total;
        $tmp["thu_p_total"] = $thu_p_total;
        $tmp["thu_a_total"] = $thu_a_total;
        $tmp["fri_p_total"] = $fri_p_total;
        $tmp["fri_a_total"] = $fri_a_total;
        $tmp["sat_p_total"] = $sat_p_total;
        $tmp["sat_a_total"] = $sat_a_total;
        array_push($row_array, $tmp);
    }
    $stmt->close();

    echo json_encode($row_array);