sql全选所有记录

Question

so there is 3 tables

1 passanger detail

2 booking

3 flight

passanger

+----+------+
| id | name |
+----+------+
|  1 | A    |
|  2 | B    |
|  3 | C    |
+----+------+

booking

+----+-------+
| id |flight |
+----+-------+
|  1 |   101 |
|  1 |   102 |
|  1 |   103 |
|  2 |   101 |
|  3 |   104 |
|  2 |   105 |
+----+-------+

flight

+--------+------+
| flight | late |
+--------+------+
|    101 |   80 |
|    102 |   80 |
|    103 |   80 |
|    104 |   10 |
|    105 |   10 |
+--------+------+

table 1 contains passnger id and name

table 2 contains passanger id and its flight id

table 3 contains flight id and how much minute it is late

now i want to find out name of the passanger whose all flights are 50 minutes late or more

so the output will be A because 101 102 and 103 are late by 80 min

not B because 101 is 80 mins late but 105 is 10 mins late (not all of b's flights are late by 50)

so my approach is

select name from passanger,booking where passanger.id=booking.id and booking.flight = ALL (select flight.flight from flight where flight.late>50)

can't get the desired output.

Answer 1

You can group by name and check if all the flights of a passenger are late with a having condition.

select p.name 
from passanger p
join booking b on p.id=b.id
join flight f on f.flight = b.flight 
group by p.name
having count(*) = count(case when f.late>50 then f.flight end)

Answer 2

Try this one:

select name from passanger, booking
where passanger.id = booking.id 
and booking.flight in (select flight.flight from flight 
                       where flight.late > 50)

or

select name from passanger, booking, flight
where passanger.id = booking.id and booking.flight = flight.flight and flight.late > 50

This will result in a's name 3 times and b's name once but if you want to get only one instance of a and b in the result, you can use select distinct name .

Answer 3

 select ps.name from passanger ps left join booking bk on (ps.id = bk.id) left join flight fl on (fl.flight = bk.flight) where  late >50