django - query - most recent entry by user

Question

Hello guys:

here is my model

class gameUserTrophyInfo(models.Model):
   user    = models.ForeignKey(userInfo)
   trophy  = models.ForeignKey(gameTrophyInfo)
   date    = models.DateTimeField()

i want a query that returns to me: for all users, return the most recent trophy.

Example:

my db:

date (Day - Month - Year )

| user | trophy | date              |
| 1    |      1 | 10-10-10 10:00:00 |
| 1    |      2 | 10-10-10 09:00:00 |
| 2    |      1 | 10-10-10 01:00:00 |
| 2    |      2 | 11-10-10 01:00:00 |
| 3    |     10 | 20-10-10 01:00:00 |

returns:

| user | trophy | date              |
|    1 |      1 | 10-10-10 10:00:00 |
|    2 |      2 | 11-10-10 01:00:00 |
|    3 |     10 | 20-10-10 01:00:00 |

how can i do that ?

thanks !

Answer 1

You need two queries:

users = User.objects.annotate(max_trophy_info_id=Max('gameusertrophyinfo__id'))
ids = [user.max_trophy_info_id for user in users]
trophy_infos = gameUserTrophyInfo.objects.filter(id__in = ids)