Geographic Searches - Indexing

Overview → Latitude and Longitude → Radius Distance Searches → Indexing → Optimization

Geographic searches are specified using a $distance function. As long as there is a multi-column Omnidex index containing the latitude and longitude, the $distance function will be automatically optimized.

The following are examples of several types of geographic searches that can be optimized using the $distance function.

select      $distance(40.0, -105.0, 41.0, -106.0) 
  from 	    $omnidex 

select      $distance(40.0, -105.0, latitude, longitude), 
            latitude, longitude,
  from      geo
 where      $distance(40.0, -105.0, latitude, longitude) < 10

select      latitude, longitude,
  from      geo
  where     $distance((select      latitude, longitude 
                         from      zipcodes 
                         where     zip = ‘80301’),
                      latitude, longitude) < 10

select      latitude, longitude,
  from      geo
 where      $distance((select      latitude, longitude 
                         from      zipcodes 
                        where      region = 'MT'),
                      latitude, longitude) < 10