The ST_DISTANCE function calculates the shortest distance, measured as a geodesic arc between two GEOGRAPHY objects, measured in meters. It models the earth as a perfect sphere with a fixed radius of 6,371,008 meters. If either input is empty, ST_DISTANCE will return NULL.

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Syntax

ST_DISTANCE(<geo1>, <geo2>)

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Parameters

ParameterDescriptionSupported input types
<geo1>The first GEOGRAPHY object to calculate the distance between.GEOGRAPHY
<geo2>The second GEOGRAPHY object to calculate the distance between.GEOGRAPHY

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Return Type

ST_DISTANCE returns a value of type DOUBLE PRECISION.

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Example

The following code example constructs two Points from their WKT representations: One at the Statue of Liberty in New York City, and one at the Big Ben in London. It then returns the shortest distance between them, as measured as a geodesic arc, in meters: 
SELECT ST_DISTANCE(
ST_GEOGFROMTEXT('POINT(-74.04447010745835 40.68924450077543)'),
ST_GEOGFROMTEXT('POINT(-0.12418551935155021 51.50086274661804)')
) AS result
Returns
result (DOUBLE PRECISION)
5574863.932096738