ST_Union

Syntax

ST_Union(geo);
ST_Union(geo1,geo2);

geo

The input geometry.

Type: VARCHAR(ANY)

geo1

The first input geometry.

Type: VARCHAR(ANY)

geo2

The second input geometry.

Type: VARCHAR(ANY)

Returns

A value of type VARCHAR(ANY) that contains the unified geometry.

Examples

CREATE TABLE points (PointID integer, the_geom VARCHAR(200)); 
INSERT INTO points VALUES (1, inza..ST_WKTToSQL('Point (0 0)')); 
INSERT INTO points VALUES (2, inza..ST_WKTToSQL('Point (22 0)'));
INSERT INTO points VALUES (3, inza..ST_WKTToSQL('Point (33 33)'));
INSERT INTO points VALUES (4, inza..ST_WKTToSQL('Point (44 44)'));
 
SELECT inza..ST_AsText(inza..ST_Union(the_geom)) from (SELECT the_geom from points
            order by PointID LIMIT 9999999) points; 
 
ST_ASTEXT
-----------------------------------------
MULTIPOINT (44 44, 33 33, 22 0, 0 0)
(1 row)

SELECT inza..ST_AsText(inza..ST_Union(inza..ST_WKTToSQL('POLYGON ((0 0, 5 0, 5 5, 0 5, 0
            0))'), inza..ST_WKTToSQL('POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))')));
 
ST_ASTEXT
-----------
MULTIPOLYGON (((0 0, 5 0, 5 5, 0 5, 0 0)), ((10 10, 10 20, 20 20, 20 15, 10 10)))
(1 row)