MySQL geo-lookup query needed

This is all simplified, but should be enough to complete the task :- I have a primary table; `providers` id (bigint) name location (point) radiusKm (int) I use a stored procedure to retrieve any providers within catchment (simplified); SELECT id, name, location, degToMeter(st_distance(@checkPoint, location)) AS distance FROM providers WHERE degToMeter(st_distance(@checkPoint, location)) < radiusKm However, I have now needed to add an additional table to account for additional depots; `depots` id (bigInt) providerId (bigint) location (point) radiusKm (smallint) The procedure must now return all providers that have a depot within the vicinity of a given point. The resulting fields I will need are :- id - The provider ID name - The provider name depotId - ID of the provider's closest depot location - location of the provider's closest depot distance - The distance of the checkPoint to the selected depot So we need a grouping of the depots for each provider, ordered by distance, with only the closest one being returned. i.e. If two depots of a single provider are within catchment, the returned provider would only show the closest one, and not return the same provider twice. I'm looking for something efficient and elegant. Many thanks.