Question

I have a SQLite table with fields Latitude and Longitude (neg and pos numbers)

I have a latitude *delta* and a longitude *delta* of (for example ’23’) based on a Latitude of 50 and a longitude of 75 (again, for example)

How do I query the table for a list of all records which are + or – 23 latitudes and + or – 23 longitudes when there are both positive and negative latitude and longitude values in the table.

The lat/long fields are of type NUMERIC and are indexed ASC.

select [fields] 
   from [table] 
      where latitude of 50 -+23 and
            longitude of 75 -+23 

Answer 1

1. Lookup the delta and stating values first
2. Calculate the +/- values based on the delta and the starting values per-record
3. Use the “BETWEEN operator” to get the result (scroll down on that link to find the info)

If you’re using an ORM between you and the database, or a programming language on top of the DB, you might be able to do steps 1 and 2 on the fly, thereby only executing one DB query in step 3.