#26178: Weird Queryset Result
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Reporter: heseba | Owner: nobody
Type: Uncategorized | Status: new
Component: Database layer (models, ORM) | Version: 1.9
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
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We want to count how often any airport appears as inbound or outbound
airport and the sum for a given set of flights for statistics purposes.
{{{
flights = .... # flight queryset
Airport.objects.filter(Q(outbound_flights__in=flights) |
Q(inbound_flights__in=flight))\
.annotate(
flight_count=Count('outbound_flights') +
Count('inbound_flights'),
outbound_flight_count=Count('outbound_flights'),
inbound_flight_count=Count('inbound_flights'),
)
}}}
Supposed we have around 80 flights, so we expect **at most** 160 in the
counts of any airport.
However, we get around 760 for the total count of the most frequent
airport. Other numbers exceed the expected values as well.
What's wrong here?
Note: {{{outbound_flights}}} and {{{inbound_flights}}} are the reverse
ForeignKeys of the model Airport and obviously each flight has one arrival
and one departure airport.
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Ticket URL: <https://code.djangoproject.com/ticket/26178>
Django <https://code.djangoproject.com/>
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