Converting MySQL into Flask-SQLAlchemy

Question

Am currently trying to convert an MySQL statement that I have written into using the functionality of SQLAlchemy

What I have is a table Project and one for Likes . These contain likes of the project. I want to get all of the specific user Projects and get the corresponding like counts.

This is the MYSQL:

SELECT project.id as id, project.name as name, 
   project.description as description, 
   project.user_id as user_id, 
   iFNULL(like_count,0) as like_count,
   project.created_on
   FROM milo.project LEFT JOIN (
       SELECT COUNT(*) as like_count, project_id 
           FROM milo.likes 
           GROUP BY project_id
   ) counting 
ON counting.project_id = milo.project.id 
WHERE (milo.project.user_id = 1) 
ORDER BY project.created_on

So this Joins a table Project to another table created through a query which counts the likes of that project

This query gets the Like counts:

res = db.session.query(func.count(likes.Likes.project_id), project.Project) \
        .join(project.Project, (likes.Likes.project_id == project.Project.id)) \
        .group_by(likes.Likes.project_id)

This query gets the user projects:

user_projects = Project.query.filter_by(user_id=1).all()

The closest I got to this, is the following:

projects = db.session.query(func.count(Likes.project_id), Project) \
        .join(Project, (Project.id == Likes.project_id)) \
        .filter(Likes.user_id == user.id) \
        .group_by(Likes.project_id).order_by(Project.created_on.desc()) \
        .all()

But the issue with this, is that if a Project has no likes, it is not returned! Clearly it also needs a Left Join, which I cannot find here.

Could anyone help with the translation of this statement?

Answer 1

I believe that you are searching for outerjoin .

so

.join(Project, (Project.id == Likes.project_id)) \

becomes

.outerjoin(Project, (Project.id == Likes.project_id))