MySQL:jumlahkan waktu tanggal tanpa menghitung periode yang tumpang tindih dua kali

Oke, saya benar-benar mendesak Anda menguji ini dengan segala cara sebelum menggunakannya dalam produksi. Terutama uji apa yang terjadi jika ada GANDA yang tumpang tindih selama 1 rentang waktu.

Apa yang dilakukan kueri ini adalah menghitung durasi setiap rentang waktu, dan seberapa banyak tumpang tindih yang ada dengan rentang waktu lain yang memiliki id lebih tinggi.

select
    t1.id,
    t1.start_time,
    t1.end_time,
    t1.end_time - t1.start_time as duration,
    sum(
          if(t2.start_time <  t1.start_time and t2.end_time >  t1.end_time  , t1.end_time - t1.start_time, 0) -- t2 completely around t1
        + if(t2.start_time >= t1.start_time and t2.end_time <= t1.end_time  , t2.end_time - t2.start_time, 0) -- t2 completely within t1
        + if(t2.start_time <  t1.start_time and t2.end_time >  t1.start_time and t2.end_time   < t1.end_time  , t2.end_time - t1.start_time, 0) -- t2 starts before t1 starts and overlaps partially
        + if(t2.start_time <  t1.end_time   and t2.end_time >  t1.end_time   and t2.start_time > t1.start_time, t1.end_time - t2.start_time, 0) -- t2 starts before t1 ends and overlaps partially
    ) as overlap
from
    times t1
    left join times t2 on
        t2.id > t1.id --  t2.id is greater than t1.id
        and (
               (t2.start_time <  t1.start_time and t2.end_time >  t1.end_time  ) -- t2 completely around t1
            or (t2.start_time >= t1.start_time and t2.end_time <= t1.end_time  ) -- t2 completely within t1
            or (t2.start_time <  t1.start_time and t2.end_time >  t1.start_time) -- t2 starts before t1 starts and overlaps
            or (t2.start_time <  t1.end_time   and t2.end_time >  t1.end_time  ) -- t2 starts before t1 ends and overlaps
        )
group by
    t1.id

Jadi yang ingin Anda miliki pada akhirnya adalah ini:

select
    sum(t.duration) - sum(t.overlap) as filtered_duration
from
    (
        OTHER QUERY HERE
    ) as t

Jadi pada akhirnya Anda memiliki pertanyaan ini:

select
    sum(t.duration) - sum(t.overlap) as filtered_duration
from
    (
        select
            t1.id,
            t1.start_time,
            t1.end_time,
            t1.end_time - t1.start_time as duration,
            sum(
                  if(t2.start_time <  t1.start_time and t2.end_time >  t1.end_time  , t1.end_time - t1.start_time, 0) -- t2 completely around t1
                + if(t2.start_time >= t1.start_time and t2.end_time <= t1.end_time  , t2.end_time - t2.start_time, 0) -- t2 completely within t1
                + if(t2.start_time <  t1.start_time and t2.end_time >  t1.start_time and t2.end_time   < t1.end_time  , t2.end_time - t1.start_time, 0) -- t2 starts before t1 starts and overlaps partially
                + if(t2.start_time <  t1.end_time   and t2.end_time >  t1.end_time   and t2.start_time > t1.start_time, t1.end_time - t2.start_time, 0) -- t2 starts before t1 ends and overlaps partially
            ) as overlap
        from
            times t1
            left join times t2 on
                t2.id > t1.id --  t2.id is greater than t1.id
                and (
                       (t2.start_time <  t1.start_time and t2.end_time >  t1.end_time  ) -- t2 completely around t1
                    or (t2.start_time >= t1.start_time and t2.end_time <= t1.end_time  ) -- t2 completely within t1
                    or (t2.start_time <  t1.start_time and t2.end_time >  t1.start_time) -- t2 starts before t1 starts and overlaps
                    or (t2.start_time <  t1.end_time   and t2.end_time >  t1.end_time  ) -- t2 starts before t1 ends and overlaps
                )
        group by
            t1.id
    ) as t