ST_Accum
Signatures
MULTIPOINT ST_Accum(POINT geom);
MULTILINESTRING ST_Accum(LINESTRING geom);
MULTIPOLYGON ST_Accum(POLYGON geom);
GEOMETRYCOLLECTION ST_Accum(GEOMETRY geom);Description
This aggregate function constructs a GEOMETRYCOLLECTION from a column of mixed dimension Geometries.
If there is only POINTs in the column of Geometries, a MULTIPOINT is returned. Same process with LINESTRINGs and POLYGONs.
Examples
Case with same dimension geometries
CREATE TABLE input_table(geom GEOMETRY);
INSERT INTO input_table VALUES
('POINT(0 0)'),
('POINT(1 1)'),
('POINT(2 2)');
SELECT ST_Accum(geom) FROM input_table;
-- Answer: MULTIPOINT ((0 0), (1 1), (2 2))Case with mixed dimension geometries
CREATE TABLE input_table(geom GEOMETRY);
INSERT INTO input_table VALUES
('POLYGON((9 0, 9 11, 10 11, 10 0, 9 0))'),
('POLYGON((1 1, 1 7, 7 7, 7 1, 1 1))'),
('POINT(1 1)'),
('POINT(2 2)');
SELECT ST_Accum(geom) FROM input_table;
-- Answer: GEOMETRYCOLLECTION(
-- POLYGON((9 0, 9 11, 10 11, 10 0, 9 0)),
-- POLYGON((1 1, 1 7, 7 7, 7 1, 1 1)),
-- POINT(1 1), POINT(2 2))