Find all points in DB which are in the radius of a lat and long

Question

I have in DB SQL Server saved point in 2 fields- lat and long

I get point, and I want find all the points from my DB in radius of five minutes walking distance.

What's the best way to do it?

I read that there is a way to do it with GeoDanjo. But I understand that it doesn't work with SQL Server.

There also ways to do it if you save the data in geography type but it is not relevant either.

Answer 1

SELECT your-fields WHERE sqrt ( ( lat - lat1 )^2 + ( long - long1 )^2 ) < your-distance;

Where lat1 and long1 are your reference point values.

Very rough approximation for short distances (as someone noted in the comments).