Creates a polygon from a linestring representing the exterior ring and an optional list of linestrings representing interior rings.
SELECT NEW ST_Polygon( NEW ST_LineString ('LineString (-5 -1, 5 -1, 0 9, -5 -1)'), NEW ST_LineString ('LineString (-2 0, 0 4, 2 0, -2 0)'))
SQL/MM (ISO/IEC 13249-3: 2006) 8.3.2