test_postgres_cube.sql

CREATE TABLE t (
	id	int
	,p	cube
);

CREATE INDEX _idx_p ON t USING gist (p);

INSERT INTO t VALUES (1, '(1,2,3)');

EXPLAIN SELECT * FROM t WHERE p <@ '(0,0,0),(3,3,3)';

//"Index Scan using _idx_p on t  (cost=0.00..8.27 rows=1 width=36)"
//"  Index Cond: (p <@ '(0, 0, 0),(3, 3, 3)'::cube)"