ST_Points — Returns a MultiPoint containing the coordinates of a geometry.
Returns a MultiPoint containing all the coordinates of a geometry. Duplicate points are preserved, including the start and end points of ring geometries. (If desired, duplicate points can be removed by calling ST_RemoveRepeatedPoints on the result).
To obtain information about the position of each coordinate in the parent geometry use ST_DumpPoints.
M and Z coordinates are preserved if present.
This method supports Circular Strings and Curves.
This function supports 3d and will not drop the z-index.
SELECT ST_AsText(ST_Points('POLYGON Z ((30 10 4,10 30 5,40 40 6, 30 10))')); --result MULTIPOINT Z ((30 10 4),(10 30 5),(40 40 6),(30 10 4))