Question : Ideas on making this Query less CPU intensive?

SELECT @lat1= latitude,
@long1 = longitude
FROM ZipCodes
WHERE zipcodes = @ZipCode

SELECT ZipCodes ,DistanceInMiles
FROM
(
SELECT ZipCodes,3958.75 * ( Atan(Sqrt(1 - power(((Sin(@Lat1/57.2958) * Sin(latitude/57.2958)) +
(Cos(@Lat1/57.2958) * Cos(latitude/57.2958) * Cos((longitude/57.2958) - (@Long1/57.2958)))), 2)) /
((Sin(@Lat1/57.2958) * Sin(latitude/57.2958)) + (Cos(@Lat1/57.2958) * Cos(latitude/57.2958) *
Cos((longitude/57.2958) - (@Long1/57.2958)))))) DistanceInMiles
FROM ZipCodes
) a
WHERE a.DistanceInMiles <= @GivenMileRadius
--AND ZipCodes <> @ZipCode
ORDER BY DistanceInMiles

I put this as a stored procedure on my SQL server 2008, and it works.
The problem is all that trig bogs down the CPU like mad. Is there a quicker non-cpu intensive way someone can think of to do this? Maybe create new columns with some pre-calculated values that would speed up searches? The canadian side of the zip codes has over 700,000 entries (canada has a ton of zip codes!) Is there a "less trig" version of this? I don't need pinpoint accuracy. Also, The max radius will always be 50 miles.

Answer : Ideas on making this Query less CPU intensive?

I'm not sure there would be much difference in execution time, but I am a big fan of Scalar functions in a situation like this.

The scalar function would encapsulate the math your are performing. You could do something like this.

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CREATE FUNCTION [dbo].[udf_CalculateDistance] 
	(@Lat1 decimal(9,4), @Long1 decimal(9,4), @latitude decimal(9,4), @longitude decimal(9,4))
RETURNS decimal(9,4)
AS
	BEGIN
		DECLARE @Result decimal(9,4)
		SET @Result = (3958.75 * ( Atan(Sqrt(1 - power(((Sin(@Lat1/57.2958) * Sin(@latitude/57.2958)) +
    (Cos(@Lat1/57.2958) * Cos(@latitude/57.2958) * Cos((@longitude/57.2958) - (@Long1/57.2958)))), 2)) /
    ((Sin(@Lat1/57.2958) * Sin(@latitude/57.2958)) + (Cos(@Lat1/57.2958) * Cos(@latitude/57.2958) *
    Cos((@longitude/57.2958) - (@Long1/57.2958))))))

      Return @result
	END



//then in your stored proc


SELECT  @lat1= latitude,
        @long1 = longitude
FROM ZipCodes
WHERE zipcodes = @ZipCode

SELECT 
   ZipCodes ,
   dbo.udf_CalculateDistance(@lat1,@long1,a.latitude,a.longitude) as [DistanceInMiles]
FROM ZipCodes as a
WHERE a.DistanceInMiles <= @GivenMileRadius
--AND ZipCodes <> @ZipCode
ORDER BY DistanceInMiles

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