> I would normally do session.query(Foo).count() COUNT is somewhat expensive compared to just checking whether rows exist, especially if lots of rows match (2.2M rows in the example):
In [2]: %timeit -n1 -r1 EventPerson.query.count() 1 loop, best of 1: 135 ms per loop In [3]: %timeit -n1 -r1 db.session.query(EventPerson.query.exists()).scalar() 1 loop, best of 1: 2.44 ms per loop > how does this interact with filtering etc? http://docs.sqlalchemy.org/en/latest/orm/query.html#sqlalchemy.orm.query.Query.exists :P It keeps all the filters present on the query object (in that example, `self` is the existing query object) > this query is against column expressions, not entities, so eager loading is not involved. That's what I first thought, but the related OUTER JOINs are still added. Maybe a bug? https://gist.github.com/ThiefMaster/00f812a5be0ce321c91241de297dbdd0 -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
