Re: Filter object by calculating duration from start and end time

Hi Steve,

It looks like it might only work on PostgreSQL unti this bug is fixed.

Simon

Le mardi 19 janvier 2016 14:59:57 UTC-5, Steven Nash a écrit :

Hi Simon,

Thanks, I'll give that ago.

Cheers,

Steve

On Tuesday, 19 January 2016 18:52:06 UTC, Simon Charette wrote:

Hi Steve,

You can use annotate for this.

from datetime import timedelta

from django.db.models import DurationField, ExpressionWrapper, F

Entry.objects.annotate(
    duration=ExpressionWrapper(
        F('end') - F('start'), output_field=DurationField()
    )
).filter(duration__gte=timedelta(minutes=time_in_minutes)

Cheers,
Simon

Le mardi 19 janvier 2016 13:01:36 UTC-5, Steven Nash a écrit :

Hi,

Given an object such as:

class Entry(models.Model):
  start = models.TimeField()
  end = models.TimeField()

I'd like to be able to say something like:

Entry.objects.filter(F('end')-F('start')__gt=time_in_minutes)

Is there a way of doing this without implementing a separate duration field and having a setter for start and end update it?

Cheers,
Steve

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