Rails Union Queries

Question

How can I execute a union (outer join) query in rails/active record?

...
    FROM `parents`
    LEFT JOIN `child` on parents.child_id = child.id
UNION
...
    FROM `parents`
    RIGHT JOIN `child` on parents.child_id = child.id

ORDER BY rate desc, grade desc, date desc;

..using Model.joins() ?

Answer 1

There isn't currently a way to do it using the regular ActiveRecord syntax, although such an idea has been proposed: https://github.com/rails/rails/issues/939

Until such a way exists, you can accomplish your goal using the find_by_sql method, described here: http://guides.rubyonrails.org/active_record_querying.html#finding-by-sql