Categories:: Geospatial functions

ST_DISTANCE¶

Returns the minimum geodesic distance between two GEOGRAPHY or the minimum Euclidean distance between two GEOMETRY objects.

Syntax¶

ST_DISTANCE( <geography_or_geometry_expression_1> , <geography_or_geometry_expression_2> )

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Arguments¶

geography_or_geometry_expression_1: The argument must be of type GEOGRAPHY or GEOMETRY.
geography_or_geometry_expression_2: The argument must be of type GEOGRAPHY or GEOMETRY.

Returns¶

Returns a FLOAT value, which represents the distance, or NULL:

For GEOGRAPHY input values, the distance is in meters.
For GEOMETRY input values, the distance is computed with the same units used to define the input coordinates.
Returns NULL if one or more input points are NULL.

Usage notes¶

For GEOMETRY objects, the function reports an error if the two input GEOMETRY objects have different SRIDs.

Examples¶

The following examples use the ST_DISTANCE function.

GEOGRAPHY examples¶

Show the distance in meters between two points 1 degree apart along the equator (approximately 111 kilometers or 69 miles).

WITH d AS
  ( ST_DISTANCE(ST_MAKEPOINT(0, 0), ST_MAKEPOINT(1, 0)) )
SELECT d / 1000 AS kilometers, d / 1609 AS miles;

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+---------------+--------------+
|    KILOMETERS |        MILES |
|---------------+--------------|
| 111.195101177 | 69.108204585 |
+---------------+--------------+

Show the output of the ST_DISTANCE function when one or more input values are NULL:

SELECT ST_DISTANCE(ST_MAKEPOINT(0, 0), ST_MAKEPOINT(NULL, NULL)) AS null_input;

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+------------+
| NULL_INPUT |
|------------|
|       NULL |
+------------+

GEOMETRY examples¶

The following example compares the distance calculated for GEOGRAPHY and GEOMETRY input objects.

SELECT ST_DISTANCE(TO_GEOMETRY('POINT(0 0)'), TO_GEOMETRY('POINT(1 1)')) AS geometry_distance,
  ST_DISTANCE(TO_GEOGRAPHY('POINT(0 0)'), TO_GEOGRAPHY('POINT(1 1)')) AS geography_distance;

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+-------------------+--------------------+
| GEOMETRY_DISTANCE | GEOGRAPHY_DISTANCE |
|-------------------+--------------------|
|       1.414213562 |   157249.628092508 |
+-------------------+--------------------+

For additional examples, see Examples comparing the GEOGRAPHY and GEOMETRY data types.