SqlAlchemy - Filtering by Relationship Attribute

Use method has() of relationship (more readable):

patients = Patient.query.filter(Patient.mother.has(phenoscore=10))

or join (usually faster):

patients = Patient.query.join(Patient.mother, aliased=True)\                    .filter_by(phenoscore=10)

python filter sqlalchemy foreign-keys

You have to query the relationsip with join

You will get the example from this Self-Referential Query Strategies

python filter sqlalchemy foreign-keys

Good news for you: I recently made package that gives you filtering/sorting with "magical" strings as in Django, so you can now write something like

Patient.where(mother___phenoscore=10)

It's a lot shorter, especially for complex filters, say,

Comment.where(post___public=True, post___user___name__like='Bi%')

Hope you will enjoy this package

CodeHunter