ST_Split-PolarDB(PolarDB)-阿里云帮助中心

Splits a geometry into parts using a blade geometry and returns the result as a GeometryCollection.

Syntax

geometry ST_Split(geometry input, geometry blade);

Parameters

Parameter	Description
`input`	The geometry object to split.
`blade`	The geometry object used to cut `input`.

Description

ST_Split supports the following input/blade combinations:

Splitting a line using a MultiPoint, MultiLine, or MultiPolygon object.
Splitting a MultiPolygon using a line object.

The function always returns a GeometryCollection. Applying ST_Union to the result theoretically reconstructs the original input geometry.

When blade is a MultiPolygon, the split uses the boundaries of the MultiPolygon, not its interior area.

Examples

Split a polygon by a line

SELECT blade,
       ST_Split(input, blade)
FROM (
    SELECT ST_MakeEnvelope(0, 0, 2, 2) AS input,
           'LINESTRING(1 -1, 1 3)'::geometry AS blade
) AS t;