Help with Database Query for Codeigniter App

I need some assistance with a codeigniter app. Perfex CRM will be a plus but not really required. I have a coding background, but I am not familiar with codeigniter. 1. I'm adding a map which takes lat/long details from a list of filtered clients as markers on a map 2. The page has an existing data table populated with a list of clients details 3. I simply need someone to write a query that provides an array of lat/long from the filtered results so I can use them with the map. I'll provide ftp details once project is approved.