ST_RemovePoint-PolarDB(PolarDB)-阿里云帮助中心

Removes a point at the specified index from a LineString geometry.

Syntax

geometry ST_RemovePoint(geometry linestring, integer offset);

Parameter	Description
`linestring`	The LineString geometry to modify.
`offset`	The zero-based index of the point to remove.

The index is zero-based: the first point has index 0.
Use this function to convert a closed ring into an open LineString by removing the duplicate end point.
Supports 3D geometries and preserves Z coordinates.

Remove the first point from a LineString

SELECT ST_AsText(ST_RemovePoint(ST_GeomFromText('LINESTRING(2 1,1 1,1 0)'), 0));

Output:

      st_astext
---------------------
 LINESTRING(1 1,1 0)
(1 row)