On 20/10/06, DavidA <[EMAIL PROTECTED]> wrote:
>
>
> Russell Keith-Magee wrote:
> > On 10/19/06, zenx <[EMAIL PROTECTED]> wrote:
> > >
> > > I want to get the maximum and the minimum values of various numbers. Is
> > > the following method the best way to do it?
> >
> > The most efficient way would be to use SQL; this way, the min and max
> > would fall out as the result of a single query.
> >
> > Unfortunately, this requires some fairly complex use of aggregate
> > clauses. The only support that Django provides for these clauses is as
> > part of the extra clause.
>
> I take it 'tag' is a ManyToMany field in 'artista'? Assuming your app
> is named 'app', you should be able to do something like this:
>
> from django.db import connection
> ...
> cursor = connection.cursor()
> cursor.execute("""
> select min(c), max(c)
> from (select tag_id, count(*) as c from app_artista_tags group by
> tag_id) s""")
> (min_c, max_c) = cursor.fetchall()[0]
> cusor.close()
>
> I find some things are easier (and faster) to do in SQL so its not
> necessarilly a bad thing to drop down to custom SQL.
Yes, dropping down is a good thing. You'll never be able to do
everything with django's simple ORM. Raw SQL is a 'good thing',
honest. Once we get SQLAlchemy we can drop to that some of the time
but until then SQL is the way forward.
> -Dave
>
>
> >
>
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