SELECT
    Total_Jam,
    Inbound_jam,
    Sorter_jam,
    1 AS Total_perc,
    Inbound_jam / Total_Jam AS Inbound_perc,
    Sorter_jam / Total_Jam AS Sorter_perc,
    Startstamp,
    Endtstamp
FROM
(
    SELECT
        MIN(jam_area.t_stamp) AS Startstamp,
        MAX(jam_area.t_stamp) AS Endtstamp,
        SUM(IFNULL(Inbound_jam, 0) + IFNULL(Sorter_jam, 0)) AS Total_Jam,
        SUM(jam_area.Inbound_jam = 1) AS Inbound_jam,
        SUM(jam_area.Sorter_jam = 1) AS Sorter_jam
    FROM jam_area
    WHERE jam_area.t_stamp BETWEEN :starttime AND :endtime
) AS basajam;