I am using Django 1.6 with Mysql.
I have these models:
class Student(models.Model):
username = models.CharField(max_length=200, unique = True)
class Score(models.Model)
student = models.ForeignKey(Student)
date = models.DateTimeField()
score = models.IntegerField()
I want to get the latest score record for each student.
I have tried:
Score.objects.values('student').annotate(latest_date=Max('date'))
and:
Score.objects.values('student__username').annotate(latest_date=Max('date'))
as described Django ORM - Get the latest record for the group but it did not help.
If your DB is postgres which supports distinct()
on field you can try
Score.objects.order_by('student__username', '-date').distinct('student__username')
This should work on Django 1.2+ and MySQL:
Score.objects.annotate(
max_date=Max('student__score__date')
).filter(
date=F('max_date')
)
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