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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/ref/contrib/postgres/aggregates.txt | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/docs/ref/contrib/postgres/aggregates.txt b/docs/ref/contrib/postgres/aggregates.txt index 6d85d5c478..9223f17ab8 100644 --- a/docs/ref/contrib/postgres/aggregates.txt +++ b/docs/ref/contrib/postgres/aggregates.txt @@ -125,7 +125,8 @@ General-purpose aggregation functions .. class:: JSONBAgg(expressions, distinct=False, filter=None, default=None, ordering=(), **extra) Returns the input values as a ``JSON`` array, or ``default`` if there are - no values. + no values. You can query the result using :lookup:`key and index lookups + <jsonfield.key>`. .. attribute:: distinct @@ -145,6 +146,29 @@ General-purpose aggregation functions Examples are the same as for :attr:`ArrayAgg.ordering`. + Usage example:: + + class Room(models.Model): + number = models.IntegerField(unique=True) + + class HotelReservation(model.Model): + room = models.ForeignKey('Room', on_delete=models.CASCADE) + start = models.DateTimeField() + end = models.DateTimeField() + requirements = models.JSONField(blank=True, null=True) + + >>> from django.contrib.postgres.aggregates import JSONBAgg + >>> Room.objects.annotate( + ... requirements=JSONBAgg( + ... 'hotelreservation__requirements', + ... ordering='-hotelreservation__start', + ... ) + ... ).filter(requirements__0__sea_view=True).values('number', 'requirements') + <QuerySet [{'number': 102, 'requirements': [ + {'parking': False, 'sea_view': True, 'double_bed': False}, + {'parking': True, 'double_bed': True} + ]}]> + .. deprecated:: 4.0 If there are no rows and ``default`` is not provided, ``JSONBAgg`` |