import sqlalchemy
def index_in(col, valuelist):
return sqlalchemy.case([(value,idx) for idx,value in enumerate
(valuelist)], value=col)
session.query(C).filter(C.someattr.in_(valuelist)).order_by(index_in
(C.someattr, valuelist))
Don't try to do this with huge lists of items.
On Feb 25, 5:53 pm, Gunnlaugur Briem <gunnlau...@gmail.com> wrote:
> Hi all,
>
> having a x IN y query, with y supplied as input to the query:
>
> session.query(C).filter(C.someattr.in_(valuelist))
>
> is there a way to tell SQLAlchemy to order the results according to
> valuelist? I.e. not by the natural order of someattr, but by the
> arbitrary order seen in valuelist? E.g.:
>
> session.add(C(someattr='Abigail'))
> session.add(C(someattr='Benjamin'))
> session.add(C(someattr='Carl'))
> valuelist = ['Benjamin', 'Abigail']
> q = session.query(C).filter(C.someattr.in_(valuelist)).order_by(clever
> (valuelist))
> q.all()
> # returns [C('Benjamin'), C('Abigail')]
>
> The solution I can think of is to create a temporary table with
> sess.execute('create temp table ...'), insert the valuelist into that
> temp table along with a sequence index, join to that temporary table
> and order by its index. Is there a less kludgy way?
>
> Regards,
>
> - Gulli
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