Yeah that almost works. I needed to add an and_ around each of the
subclauses, otherwise the or_ breaks.
abcd = or_(and_(table.col_1 == a, table.col_2 == b),
and_(table.col_1 == b, table.col_2 == c))
For posterity, to loop over my rows I found I could put it in a generator
over the columns
col1 = list of column 1
col2 = list of column 2
or_(and_(table.col_1==p, table.col_2==col2[i]) for i,p in enumerate(col1))
Thanks for the help.
On Tuesday, October 27, 2015 at 2:05:31 PM UTC+11, Brian Cherinka wrote:
>
>
> What's the best way to query, with the ORM, based on a list of multiple
> parameters without looping over each parameter tuple?
>
> I have a list of parameters say:
>
> Col-1, Col-2
> a, b
> c, d
>
> where the combination of the parameters in one row defines a unique table
> entry. Such that I would normally do
>
> object = session.query(table).filter(table.Col-1 == a, table.Col-2 ==
> b).one() , and
> object = session.query(table).filter(table.Col-1 == c, table.Col-2 ==
> d).one()
>
> to retrieve the two table objects
>
> Can I run a query that would grab the list of objects all at once, in one
> query, without having to loop over each row, doing each query, and
> combining the objects into a list? Something akin to the
> table.Col-1..in_([list of values) but with a combinatorial component to it.
>
>
> I know I can do something like
> session.query(table).filter(table.Col-1.in_([a,c]).all() to grab all the
> objects that have column 1 values of a, or c, but I need to constrain those
> to a+b, and c+d
>
> Does this make sense?
>
> Cheers, Brian
>
>
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