ST_StartPoint
Signature
POINT ST_StartPoint(GEOMETRY geom);
Description
Returns the first coordinate of geom as a POINT, given that geom is a
LINESTRING or a MULTILINESTRING containing only one LINESTRING. Returns
NULL for all other Geometries.
Note
Implements the OpenGIS Simple Features Implementation Specification for SQL version 1.2.1
Example
SELECT ST_StartPoint('LINESTRING(1 2, 5 3, 2 6)');
-- Answer: POINT(1 2)

SELECT ST_StartPoint('MULTILINESTRING((1 1, 3 2, 3 1))');
-- Answer: POINT(1 1)
SELECT ST_StartPoint('MULTILINESTRING((1 1, 3 2, 3 1),
(1 2, 5 3, 2 6))');
-- Answer: NULL