ST_SetPoint

Introduction: Replace Nth point of linestring with given point. Index is 0-based. Negative index are counted backwards, e.g., -1 is last point.

Format: ST_SetPoint (linestring: geometry, index: integer, point: geometry)

Example:

SELECT ST_SetPoint(ST_GeomFromText('LINESTRING (0 0, 0 1, 1 1)'), 2, ST_GeomFromText('POINT (1 0)')) AS geom

Result:

+--------------------------+
|geom                      |
+--------------------------+
|LINESTRING (0 0, 0 1, 1 0)|
+--------------------------+