ST_GeometryN takes a collection and an integer index and returns the nth ST_Geometry object in the collection.
Oracle
sde.st_geometryn (mpt1 sde.st_multipoint, index integer)
sde.st_geometryn (mln1 sde.st_multilinestring, index integer)
sde.st_geometryn (mpl1 sde.st_multipolygon, index integer)
PostgreSQL
st_geometryn (mpt1 st_multipoint, index integer)
st_geometryn (mln1 st_multilinestring, index integer)
st_geometryn (mpl1 st_multipolygon, index integer)
In this example, a multipolygon is created. Then ST_GeometryN is used to list the second element of the multipolygon.
Oracle
CREATE TABLE districts (dist_id integer, shape sde.st_multipolygon);
INSERT INTO districts (dist_id, shape) VALUES (
1,
sde.st_multipolygon ('multipolygon (((-1 -1, -1 11, 11 11, 11 -1, -1 -1),
(19 -1, 19 11, 29 9, 31 -1, 19 -1), (39 -1, 39 11, 51 11, 51 -1, 39 -1)))', 0)
);
SELECT sde.st_astext (sde.st_geometryn (shape, 2)) Second_Element
FROM districts;
Second_Element
POLYGON ((-1.00000000 -1.00000000, 11.00000000 -1.00000000, 11.0000000 0 11.000
PostgreSQL
CREATE TABLE districts (dist_id integer, shape st_geometry);
INSERT INTO districts (dist_id, shape) VALUES (
1,
st_multipolygon ('multipolygon (((-1 -1, -1 11, 11 11, 11 -1, -1 -1),
(19 -1, 19 11, 29 9, 31 -1, 19 -1), (39 -1, 39 11, 51 11, 51 -1, 39 -1)))', 0)
);
SELECT st_astext (st_geometryn (shape, 2)) AS Second_Element
FROM districts;
Second_Element
POLYGON ((39 -1, 51 -1, 51 11, 39 11, 39 -1))
