On 12/01/2016 09:13 AM, Adrian wrote:
Is there any shorter/prettier way for this?

    session.query(session.query(Foo).exists()).scalar()


I would normally do


session.query(Foo).count()

I've never embedded an EXISTS like that.



It's not hard to add a custom method to the base query class that returns

    self.session.query(self.exists()).scalar()

how does this interact with filtering etc? seems like this method would work just like count().



but it feels like something that should be part of SQLAlchemy.

Also, is there any case where `.enable_eagerloads(False)` right before
`.exists()` could cause problems / different results?

this query is against column expressions, not entities, so eager loading is not involved.

If not, wouldn't it make sense for exists() to do that automatically?
Loading a relationship doesn't ever seem to make sense
when checking exists().

there's no entity loaded so relationships aren't involved.



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