Ok, insisto seriamente sul fatto che tu lo provi in tutti i modi prima di usarlo in produzione. Verifica in particolare cosa succede se ci sono più sovrapposizioni per 1 intervallo di tempo.
Ciò che fa questa query è calcolare la durata di ogni intervallo di tempo e quanta sovrapposizione esiste con altri intervalli di tempo che hanno un ID maggiore.
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
Quindi quello che vuoi avere alla fine è questo:
select
sum(t.duration) - sum(t.overlap) as filtered_duration
from
(
OTHER QUERY HERE
) as t
Quindi alla fine hai questa domanda:
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
