Please advice if there is a more performant or better looking solution for
my problem. Thank you.
On Monday, July 31, 2017 at 5:15:41 PM UTC-7, Federico Delgado wrote:
>
> Hi,
>
> I am having problems trying to figure out this.
>
> Using: SqlAlchemy 1.1.12
> PostgreSQL: 9.6
> Python: 2.7.13
>
> I have a simple entity:
>
> class Package(Base):
> __tablename__ = 'package'
> id = Column(Integer, primary_key=True)
> name = Column(String(255))
>
>
> and a function in my DB that performs some operations and returns just a
> list of IDs in a particular order that I have to maintain. This function is
> called 'calculate_rankings' and returns a table. The first lines are:
>
> CREATE OR REPLACE FUNCTION public.calculate_rankings(pattern text)
> RETURNS TABLE(id integer, weight bigint)
> LANGUAGE 'sql'
>
>
> So ideally I'd like to do something like (this is just a sample):
>
> my_function = func.calculate_rankings('somestring')
> session.query(Packages).filter(Packages.id == my_function.id
> ).order_by(my_function.weight).all()
>
> I have tried multiple ways to accomplish this. Like using:
>
> my_function = select([column('id'),
> column('weight')]).select_from(func. calculate_rankings('somestring'))
>
> But that results in a 'select' that I cannot use inside the query.
>
> but the most I could get is using in_ to ensure I am getting the correct
> packages. For that I also had to drop the all important column weight.
>
> Maybe somebody can point me to the right resource?
>
> Thank you,
>
> Federico
>
>
>
>
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