카테고리:

지리 공간 함수

ST_LENGTH

Returns the geodesic length of the LineString(s) in a GEOGRAPHY object or the Euclidean length of the LineString(s) in a GEOMETRY object.

구문

ST_LENGTH( <geography_or_geometry_expression> )

인자

geography_or_geometry_expression

The argument must be of type GEOGRAPHY or GEOMETRY.

반환

길이를 미터 단위로 나타내는 REAL 값을 반환합니다.

사용법 노트

  • If geography_or_geometry_expression is not a LineString, MultiLineString, or GeometryCollection containing linestrings, ST_LENGTH returns 0.

  • If geography_or_geometry_expression is a GeometryCollection, ST_LENGTH returns the sum of the lengths of the linestrings in the collection.

  • 다각형의 둘레 길이를 원하는 경우, 대신 ST_PERIMETER 함수를 사용하십시오.

GEOGRAPHY Examples

이는 적도에서 호 1도의 길이를 미터 단위로 보여줍니다.

SELECT ST_LENGTH(TO_GEOGRAPHY('LINESTRING(0.0 0.0, 1.0 0.0)'));
+---------------------------------------------------------+
| ST_LENGTH(TO_GEOGRAPHY('LINESTRING(0.0 0.0, 1.0 0.0)')) |
|---------------------------------------------------------|
|                                        111195.101177484 |
+---------------------------------------------------------+

GEOMETRY Examples

The following example demonstrates how to use the ST_LENGTH function.

SELECT ST_LENGTH(g), ST_ASWKT(g)
FROM (SELECT TO_GEOMETRY(column1) AS g
  FROM VALUES ('POINT(1 1)'),
              ('LINESTRING(0 0, 1 1)'),
              ('POLYGON((0 0, 0 1, 1 1, 1 0, 0 0))'));
+--------------+--------------------------------+
| ST_LENGTH(G) | ST_ASWKT(G)                    |
|--------------+--------------------------------|
|  0           | POINT(1 1)                     |
|  1.414213562 | LINESTRING(0 0,1 1)            |
|  0           | POLYGON((0 0,0 1,1 1,1 0,0 0)) |
+--------------+--------------------------------+
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