Flask SQLAlchemy display queries for debug

I haven't used it myself, but it seems that Flask Debug-toolbar may help with this.

https://github.com/mgood/flask-debugtoolbar

It's a port of the django-debug-toolbar, which can be used for profiling queries. The documentation of Flask Debug-toolbar doesn't mention it, but there is code for a SQLAlchemyDebugPanel.
So I think it may be well worth to take a look at the project, and see if it does what you need.

app.config['SQLALCHEMY_ECHO'] = True

If you're using the Flask-SQLAlchemy extension and don't want to bother with create_engine, you can set the configuration key SQLALCHEMY_ECHO=True.

http://flask-sqlalchemy.pocoo.org/2.1/config/