1Boundary - closed linestring
2:memory: #use in-memory database
3SELECT AsText(Boundary(GeomFromText('LINESTRING(1 2, 4 -3, 0 -1, 1 2)')))
41 # rows (not including the header row)
51 # columns
6AsText(Boundary(GeomFromText('LINESTRING(1 2, 4 -3, 0 -1, 1 2)')))
7(NULL)
8