Calculate Distance Between Two Zip Codes Sql

How to Calculate Distance Between Two Zip Codes in SQL

Have you ever wondered how to calculate the distance between two zip codes in SQL Whether you need to find the nearest store, restaurant, or customer, knowing how to calculate the distance between zip codes can be very useful. In this article, we will show you how to do it using different SQL platforms and techniques.

What is a Zip Code

A zip code is a postal code used in the United States and some other countries to identify a specific location. A zip code consists of five digits, such as 90210 or 10001. Some zip codes may have an optional four-digit extension, such as 90210-1234 or 10001-0001.

What is a Latitude and Longitude

A latitude and longitude are coordinates that specify the exact position of a point on the Earth's surface. A latitude is a measure of how far north or south a point is from the equator, while a longitude is a measure of how far east or west a point is from the prime meridian. A latitude and longitude are expressed in degrees, minutes, and seconds, such as 34Â03'08.4\"N 118Â14'37.5\"W or 40Â44'55.3\"N 73Â59'11.0\"W.

How to Calculate Distance Between Two Zip Codes in SQL

To calculate the distance between two zip codes in SQL, we need to use some mathematical formulas that take into account the curvature of the Earth and the spherical geometry of its surface. One of the most common formulas is called the Haversine formula, which calculates the great-circle distance between two points on a sphere.

The Haversine formula is given by:

```math

d = 2r \\arcsin \\sqrt{\\sin^2 \\left(\\frac{\\phi_2 - \\phi_1}{2}\\right) + \\cos \\phi_1 \\cos \\phi_2 \\sin^2 \\left(\\frac{\\lambda_2 - \\lambda_1}{2}\\right)}

```

where:

d is the distance between two points

r is the radius of the sphere (in this case, the Earth)

$\\phi_1$ and $\\phi_2$ are the latitudes of the two points

$\\lambda_1$ and $\\lambda_2$ are the longitudes of the two points

To use this formula in SQL, we need to convert the latitudes and longitudes from degrees to radians, and then apply some trigonometric functions. We also need to convert the distance from radians to miles or kilometers, depending on our preference.

Here is an example of how to calculate the distance between two zip codes in SQL Server:

```sql

-- Declare variables for zip codes

DECLARE @zip1 VARCHAR(10) = '90210'

DECLARE @zip2 VARCHAR(10) = '10001'

-- Declare variables for radius of Earth

DECLARE @r_miles FLOAT = 3959 -- in miles

DECLARE @r_km FLOAT = 6371 -- in kilometers

-- Declare variables for latitudes and longitudes

DECLARE @lat1 FLOAT

DECLARE @lng1 FLOAT

DECLARE @lat2 FLOAT

DECLARE @lng2 FLOAT

-- Get latitudes and longitudes from a table of zip codes

SELECT @lat1 = latitude, @lng1 = longitude FROM ZipCodes WHERE zipcode = @zip1

SELECT @lat2 = latitude, @lng2 = longitude FROM ZipCodes WHERE zipcode = @zip2

-- Convert degrees to radians

SET @lat1 = RADIANS(@lat1)

SET @lng1 = RADIANS(@lng1)

SET @lat2 = RADIANS(@lat2)

SET @lng2 = RADIANS(@lng2)

-- Apply Haversine formula

DECLARE @d_radians FLOAT -- distance in radians

DECLARE @d_miles FLOAT -- distance in miles

DECLARE @d_km FLOAT -- distance in kilometers

SET @d_radians = aa16f39245