Django ORM query modelling question

[Carsten Fuchs]

Dear Django list,




The (simplified) Django model is


class Erfasst(models.Model):
    datum = models.DateField()
    info  = models.BigIntegerField()


An example for the contents of this model is, pre-sorted by 'datum':

datum              info
-----------------------
2011-FEB-01        4         *
2011-FEB-02        4
2011-FEB-03        4
2011-FEB-04        5         *
2011-FEB-05        5
2011-FEB-06        5
2011-FEB-07        5
2011-FEB-08        1         *
2011-FEB-09        1
2011-FEB-10        4         *
2011-FEB-11        4





I tried

    Erfasst.objects.values('info').annotate(Min('datum'))



    Erfasst.objects.order_by('datum').values('info').annotate(Min('datum'))




What is the correct query for the task?

Thank you very much!

Best regards,
Carsten

after a very good start with Django and it's excellent documentation, I've come now across a problem that neither my SQL nor my Django knowledge is sufficient to solve, so I'd like to ask for your kind help. What I would like to know are the rows, when ordered by 'datum', whose 'info' changed (those marked with a star above). but that doesn't work, because it groups all rows with e.g. 'info'==4 and thus doesn't report the row with (datum: 2011-FEB-10, info: 4). doesn't work either, because it groups the ('datum', 'info') pairs, which is one row per group.

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