Question

I have model with a location, which itself has a latitude and longitude. What I want is the Deal whose lat/long are within a certain region, so I tried this:

boundary = self.user.boundary
max_lat, max_lng = boundary.max_coords.latitude, boundary.max_coords.lng
min_lat, min_lng = boundary.min_coords.latitude, boundary.min_coords.lng
lat, long = self.user.location.latitude, self.user.location.longitude
self.all_deals =  Deal.where('location.latitude <= ? AND location.latitude >= ? AND location.longitude <= ? AND location.longitude >= ?', max_lat, min_lat, max_lng, min_lng).limit(10)

SQL raises an exception saying there isn’t a column ‘location.latitude’. How can I write the same thing but either using ActiveRecord (preferred) or in raw SQL?

Answer 1

You are missing the joins on this query.

To be able to use location you have to rewrite the query:

self.all_deals =  Deal.joins(:location).where('location.latitude <= ? AND location.latitude >= ? AND location.longitude <= ? AND location.longitude >= ?', max_lat, min_lat, max_lng, min_lng).limit(10)

If you look at the generated SQL it now should include a join over the deal.location_id.
(I am assuming location is a referenced model that is connected to your deal throuh a belongs_to or has_one relation?)

See more info on joins in the docs