ST_IsEmpty returns 1 (Oracle) or t (PostgreSQL) if the geometry is empty; otherwise, it returns 0 (Oracle) or f (PostgreSQL).
Oracle
sde.st_isempty (g1 sde.st_geometry)
PostgreSQL
st_isempty (g1 st_geometry)
The CREATE TABLE statement below creates the empty_test table with geotype, which stores the data type of the subclasses that are stored in the g1 ST_Geometry column.
The INSERT statements insert two records for the geometry subclasses point, linestring, and polygon: one that is empty and one that is not.
Oracle
CREATE TABLE empty_test (geotype varchar(20), g1 sde.st_geometry);
INSERT INTO empty_test VALUES (
'Point',
sde.st_pointfromtext ('point (10.02 20.01)', 0)
);
INSERT INTO empty_test VALUES (
'Point',
sde.st_pointfromtext ('point empty', 0)
);
INSERT INTO empty_test VALUES (
'Linestring',
sde.st_linefromtext ('linestring (10.02 20.01, 10.32 23.98, 11.92 25.64)', 0)
);
INSERT INTO empty_test VALUES (
'Linestring',
sde.st_linefromtext ('linestring empty', 0)
);
INSERT INTO empty_test VALUES (
'Polygon',
sde.st_polyfromtext ('polygon ((10.02 20.01, 11.92 35.64, 25.02 34.15,
19.15 33.94, 10.02 20.01))', 0)
);
PostgreSQL
CREATE TABLE empty_test (geotype varchar(20), g1 st_geometry);
INSERT INTO empty_test VALUES (
'Point',
st_point ('point (10.02 20.01)', 0)
);
INSERT INTO empty_test VALUES (
'Point',
st_point ('point empty', 0)
);
INSERT INTO empty_test VALUES (
'Linestring',
st_linestring ('linestring (10.02 20.01, 10.32 23.98, 11.92 25.64)', 0)
);
INSERT INTO empty_test VALUES (
'Linestring',
st_linestring ('linestring empty', 0)
);
INSERT INTO empty_test VALUES (
'Polygon',
st_polygon ('polygon ((10.02 20.01, 11.92 35.64, 25.02 34.15,
19.15 33.94, 10.02 20.01))', 0)
);
The SELECT query returns the geometry type from the geotype column and the results of the ST_IsEmpty function.
Oracle
SELECT geotype, sde.st_isempty (g1) Is_it_empty
FROM empty_test;
GEOTYPE Is_it_empty
Point 0
Point 1
Linestring 0
Linestring 1
Polygon 1
PostgreSQL
SELECT geotype, st_isempty (g1) AS Is_it_empty
FROM empty_test;
geotype is_it_empty
Point f
Point t
Linestring f
Linestring t
Polygon f