Question

I have a table with the following attributes:

MyTable:
- double longitude 
- double latitude
- varchar place_id
- varcar geoJSON_string

Given some point having a longitude x and latitude y I need to select the k closest points.

I know I tack a LIMIT k on the end of the query, but is there a way I can guarantee at least k points from a database of ~250,000 records?

Also, how would I even query the decimal values? I need to select something similar to the following:

SELECT * FROM MyTable WHERE latitude=140.3**** and longitude=132.2**** LIMIT k;

Answer 1

SELECT * FROM MyTable WHERE latitude BETWEEN '140.3' AND '140.4' AND longitude BETWEEN '132.2' AND '132.3' LIMIT k;

or, if you need the best result :

SELECT * FROM MyTable ORDER BY ABS(ABS(searched-lon - longitude) - ABS(searched-lat - latitude)) ASC LIMIT k;