Добре, сериозно настоявам да тествате това по всякакъв начин, преди да го използвате в производството. Особено тествайте какво се случва, ако има НЯКОЛКО припокривания за 1 времеви интервал.
Това, което прави тази заявка, е да изчислява продължителността на всеки период от време и колко припокриване съществува с други периоди от време, които имат по-висок идентификатор.
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
Така че това, което искате да имате в крайна сметка, е това:
select
sum(t.duration) - sum(t.overlap) as filtered_duration
from
(
OTHER QUERY HERE
) as t
Така че в крайна сметка имате тази заявка:
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