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    ApsaraDB RDS:ST_Length

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    ApsaraDB RDS:ST_Length

    Last Updated:Mar 28, 2026

    Returns the 2D length of a linear geometry.

    Syntax

    float ST_Length(geometry a2dlinestring);
float ST_Length(geography geog, boolean useSpheroid);

    Parameters

    ParameterDescription
    a2dlinestringThe 2D linear geometry object.
    geogThe geography object.
    useSpheroidSpecifies whether to use an ellipsoid model.

    Description

    For geometry objects:

    • Returns the 2D Cartesian length if the input is a LineString, MultiLineString, ST_Curve, or ST_MultiCurve.

    • Returns 0 for surface geometries. To get the perimeter of a surface, use ST_Perimeter instead.

    • The unit of the result is determined by the spatial reference system (SRS) of the geometry object.

    For geography objects:

    • Returns the inverse geodesic distance in meters.

    Examples

    Calculate the length of a LineString geometry

    SELECT ST_Length('LINESTRING(0 0,1 1)'::geometry);
    st_length
-----------------
 1.4142135623731
(1 row)

    What's next

    • ST_Perimeter — Calculate the perimeter of a surface geometry or geography object