How to subtract date, then sum the results of the previous operation - mysql

Question

I have a database with table Plane, the table Flight, which is basically a Flight that a Plane did, then for each flight I have solved M:N table which just holds foreign keys for Flight and Destination, 2 entries in table Destination, to know the difference between Departure and Arrival, table Destination has a connection to table Type( Departure and Arrival, which is set in another table, of 2 rows, "Zacetna" = Departure, "Koncna" = Arrival ). Table Destination also has a connection to table Date which contains Datetime.
I want to Subtract Arrival and Departure time for each Flight, then Sum the times if Plane has multiple Flights.
I have tried to just Subtract them all and then sub but that didn't work, then I have tried to Group By, but with no luck.
In the attached picture.
Plane called "Falcon FX 3000" has 2 flights, idFlight 5 and 6. To get the expected result I would have to do
( Destination_6_Date - Destination_5_Date) + (Destination_4_Date - Destination_7_Date)
but none of my solutions worked
SELECT d.Ime, letD.Destinacija_idDestinacija, l.idLet,tip.Tip, t.Termin
FROM Letalo p
INNER JOIN Let l ON l.Letalo_idLetalo = p.idLetalo
INNER JOIN Let_Has_Destinacija letD on letD.Let_idLet = l.idLet
INNER JOIN Destinacija d on d.idDestinacija = letD.Destinacija_idDestinacija
INNER JOIN Termin t on t.idTermin = d.Termin_idTermin
INNER JOIN Tip_Destinacije tip on tip.idTip_Destinacije = Tip_Destinacije_idTip_Destinacije WHERE p.Naziv='Falcon FX 3000';
https://i.imgur.com/5r2G9yI.png
https://i.imgur.com/3CIfbUN.png
Sorry for the ERDiagram for being in the different language
Letalo = Plane
Let = Flight
Let_Has_Destinacija = Solved M:N, holding Flight ID and Destination ID
Destinacija = Destination
Termin = Date
Tip_Destinacija = Type
EDIT
This is the successful GROUP BY query that returns valid calculations, now I just need to sum them. I am guessing this will be done with subquery, but I don't really understand that, as I am new to MySQL
SELECT d.Ime as Name, letD.Destinacija_idDestinacija as Destination, l.idLet as idFlight,tip.Tip as Type, CAST(t.Termin as DATE), timediff(Max(t.Termin), min(t.Termin))
FROM Letalo p
INNER JOIN Let l ON l.Letalo_idLetalo = p.idLetalo
INNER JOIN Let_Has_Destinacija letD on letD.Let_idLet = l.idLet
INNER JOIN Destinacija d on d.idDestinacija = letD.Destinacija_idDestinacija
INNER JOIN Termin t on t.idTermin = d.Termin_idTermin
INNER JOIN Tip_Destinacije tip on tip.idTip_Destinacije = Tip_Destinacije_idTip_Destinacije WHERE p.Naziv='Falcon FX 3000'
GROUP BY l.idLet;
https://i.imgur.com/hUXZDnQ.png
EDIT 2
By using temp tables, I managed to SUM the flights times, but I have to use 2 queries for this, which is not what I want.
DROP TABLE IF EXISTS tempTime;
CREATE TEMPORARY TABLE tempTime (
SELECT timediff(Max(t.Termin), min(t.Termin)) as FlightTime
FROM Letalo p
INNER JOIN Let l ON l.Letalo_idLetalo = p.idLetalo
INNER JOIN Let_Has_Destinacija letD on letD.Let_idLet = l.idLet
INNER JOIN Destinacija d on d.idDestinacija = letD.Destinacija_idDestinacija
INNER JOIN Termin t on t.idTermin = d.Termin_idTermin
INNER JOIN Tip_Destinacije tip on tip.idTip_Destinacije = Tip_Destinacije_idTip_Destinacije WHERE p.Naziv='Falcon FX 3000'
GROUP BY l.idLet);
SELECT SEC_TO_TIME(SUM(TIME_TO_SEC(FlightTime))) as FlownTime FROM tempTime;
DROP TABLE IF EXISTS tempTime;
https://i.imgur.com/HlPtgHr.png
ACCEPTED ANSWER
SELECT
`Name`,
`Destination`,
`Type`,
`Date`,
SEC_TO_TIME(SUM(TIME_TO_SEC(`Time_diff`))) as `Tot_Diff`
FROM (
SELECT
d.`Ime` as `Name`,
letD.`Destinacija_idDestinacija` as `Destination`,
l.`idLet` as idFlight,tip.`Tip` as `Type`,
CAST(t.`Termin` as DATE) as `Date`,
timediff(Max(t.`Termin`), min(t.`Termin`)) as `Time_diff`
FROM Letalo p
INNER JOIN `Let` l
ON l.`Letalo_idLetalo` = p.`idLetalo`
INNER JOIN `Let_Has_Destinacija` letD
on letD.`Let_idLet` = l.`idLet`
INNER JOIN `Destinacija` d
on d.`idDestinacija` = letD.`Destinacija_idDestinacija`
INNER JOIN `Termin` t
on t.`idTermin` = d.`Termin_idTermin`
INNER JOIN `Tip_Destinacije` tip
on tip.`idTip_Destinacije` = `Tip_Destinacije_idTip_Destinacije`
WHERE p.Naziv = 'Falcon FX 3000'
GROUP BY l.idLet
) as `main`

Answer 1

I believe this should produce the result you describe. Basically, it takes the query you have, uses it as a sub-query
then sums the time differences.
SELECT
`Name`,
`Destination`,
`Type`,
`Date`,
SEC_TO_TIME(SUM(TIME_TO_SEC(`Time_diff`))) as `Tot_Diff`
FROM (
SELECT
d.`Ime` as `Name`,
letD.`Destinacija_idDestinacija` as `Destination`,
l.`idLet` as idFlight,tip.`Tip` as `Type`,
CAST(t.`Termin` as DATE) as `Date`,
timediff(Max(t.`Termin`), min(t.`Termin`)) as `Time_diff`
FROM Letalo p
INNER JOIN `Let` l
ON l.`Letalo_idLetalo` = p.`idLetalo`
INNER JOIN `Let_Has_Destinacija` letD
on letD.`Let_idLet` = l.`idLet`
INNER JOIN `Destinacija` d
on d.`idDestinacija` = letD.`Destinacija_idDestinacija`
INNER JOIN `Termin` t
on t.`idTermin` = d.`Termin_idTermin`
INNER JOIN `Tip_Destinacije` tip
on tip.`idTip_Destinacije` = `Tip_Destinacije_idTip_Destinacije`
WHERE p.Naziv = 'Falcon FX 3000'
GROUP BY l.idLet
) as `main`
GROUP BY `Name`,`Destination`,`Type`,`Date`;