ST_Area returns the area of a polygon or multipolygon.

Oracle

sde.st_area (pl1 sde.st_geometry)
sde.st_area (mpl1 sde.st_geometry)

PostgreSQL

st_area (pl1 st_geometry)
st_area (mpl1 st_geometry)

Double precision

The city engineer needs a list of building areas. To create the list, a GIS technician selects the building ID and area of each building's footprint.

The building footprints are stored in the bfp table created with the following CREATE TABLE statement.

Oracle

CREATE TABLE bfp (
building_id integer,
footprint sde.st_geometry);

INSERT INTO bfp VALUES (
1, 
sde.st_polygon ('polygon ((0 0, 0 10, 10 10, 10 0, 0 0))', 0)
);

INSERT INTO bfp VALUES (
2, 
sde.st_polygon ('polygon ((20 0, 30 20, 40 0, 20 0))', 0)
);

INSERT INTO bfp VALUES (
3,
sde.st_polygon ('polygon ((20 30, 25 35, 30 30, 20 30))', 0)
);

PostgreSQL

CREATE TABLE bfp (
building_id integer unique,
footprint st_geometry);

INSERT INTO bfp VALUES (
1, 
st_polygon ('polygon ((0 0, 0 10, 10 10, 10 0, 0 0))', 0)
);

INSERT INTO bfp VALUES (
2, 
st_polygon ('polygon ((20 0, 30 20, 40 0, 20 0))', 0)
);

INSERT INTO bfp VALUES (
3,
st_polygon ('polygon ((20 30, 25 35, 30 30, 20 30))', 0)
);

To satisfy the city engineer's request, the technician selects the unique key, the building_id, and the area of each building footprint from the bfp table.

Oracle

SELECT building_id, sde.st_area (footprint) Area
FROM bfp;

BUILDING_ID       Area

          1        100
          2        200
          3         25

PostgreSQL

SELECT building_id, st_area (footprint) AS Area
FROM bfp;

building_id       area

          1        100
          2        200
          3         25