How to query/join tables where foreign key constraint is set in schema
A foreign key constraint is just a constraint, i.e., it prevents you from inserting data that would violate the constraint.

Foreign key constraints have no effect on queries; if you want to join tables through these values, you still have to write the join. (Why? Because the SQL standard has always said so, so changing it would break backwards compatibility.)

The only way to avoid the ON is by giving the columns the same name in the parent and child tables so that you can use the USING clause instead:

SELECT ... FROM ParentTable JOIN ChildTable USING (ParentID);


(And this is less typing than a hypothetical ... JOIN ... USING FOREIGN KEY ConstraintName.)