ST_Intersects
Definition
ST_Intersects returns 1 (Oracle) or t (PostgreSQL) if the intersection of two ST_Geometries doesn't result in an empty set; otherwise, it returns 0 (Oracle) or f (PostgreSQL).
Syntax
sde.st_intersects (g1 sde.st_geometry, g2 sde.st_geometry)
Return type
Boolean
Example
The fire marshal wants a list of sensitive areas within a radius of a hazardous waste site.
The sensitive areas are stored in the sensitive_areas table that is created with the CREATE TABLE statement that follows. The zone column, defined as a polygon, stores the outline of each of the sensitive areas.
The hazardous sites are stored in the hazardous_sites table created with the CREATE TABLE statement that follows. The location column, defined as a point, stores a location that is the geographic center of each hazardous site.
CREATE TABLE sensitive_areas (id integer, zone sde.st_geometry); CREATE TABLE hazardous_sites (id integer, location sde.st_geometry); INSERT INTO sensitive_areas VALUES ( 1, sde.st_polygon ('polygon ((20 30, 30 30, 30 40, 20 40, 20 30))', 0) ); INSERT INTO sensitive_areas VALUES ( 2, sde.st_polygon ('polygon ((30 30, 30 50, 50 50, 50 30, 30 30))', 0) ); INSERT INTO sensitive_areas VALUES ( 3, sde.st_polygon ('polygon ((40 40, 40 60, 60 60, 60 40, 40 40))', 0) ); INSERT INTO hazardous_sites VALUES ( 4, sde.st_point ('point (60 60)', 0) ); INSERT INTO hazardous_sites VALUES ( 5, sde.st_point ('point (30 30)', 0) );
The query returns a list of sensitive areas and hazardous sites, for sensitive areas that intersect the buffer radius of the hazardous sites.
Oracle
SELECT sa.id SA_ID, hs.id HS_ID FROM SENSITIVE_AREAS sa, HAZARDOUS_SITES hs WHERE sde.st_intersects (sde.st_buffer (hs.location, .1), sa.zone) = 1 ORDER BY sa.id; SA_ID HS_ID 1 5 2 5 3 4
PostgreSQL
SELECT sa.id AS SA_ID, hs.id AS HS_ID FROM sensitive_areas sa, hazardous_sites hs WHERE sde.st_intersects (sde.st_buffer (hs.location, .1), sa.zone) = 't' ORDER BY sa.id; sa_id hs_id 1 5 2 5 3 4