SQL Query For Total Points Within Radius of a Location

Question

I have a database table of all zipcodes in the US that includes city,state,latitude & longitude for each zipcode. I also have a database table of points that each have a lat

Answer 1

SELECT * FROM tblLocation 
    WHERE 2 > POWER(POWER(Latitude - 40, 2) + POWER(Longitude - -90, 2), .5)

where the 2 > part would be the number of parallels away and 40 and -90 are lat/lon of the test point

Sorry I didn't use your tablenames or structures, I just copied this out of one of my stored procedures I have in one of my databases.

If I wanted to see the number of points in a zip code I suppose I would do something like this:

SELECT 
    ParcelZip, COUNT(LocationID) AS LocCount 
FROM 
    tblLocation 
WHERE 
    2 > POWER(POWER(Latitude - 40, 2) + POWER(Longitude - -90, 2), .5)
GROUP BY 
    ParcelZip

Getting the total count of all locations in the range would look like this:

SELECT 
    COUNT(LocationID) AS LocCount 
FROM 
    tblLocation 
WHERE 
    2 > POWER(POWER(Latitude - 40, 2) + POWER(Longitude - -90, 2), .5)

A cross join may be inefficient here since we are talking about a large quantity of records but this should do the job in a single query:

SELECT 
    ZipCodes.ZipCode, COUNT(PointID) AS LocCount 
FROM
    Points
CROSS JOIN 
    ZipCodes
WHERE 
    2 > POWER(POWER(Points.Latitude - ZipCodes.Latitude, 2) + POWER(Points.Longitude - ZipCodes.Longitude, 2), .5)
GROUP BY 
    ZipCodeTable.ZipCode