-- emptySELECT ST_AsText(ST_GeomFromGeoJSON('{"type":"Point","coordinates":[]}')) res FROM DUAL;RES
---------------------------------------------------------------- POINT EMPTY
-- pointSELECT ST_AsText(ST_GeomFromGeoJSON(ST_AsGeoJSON(ST_GeomFromText('POINT(1 1)')))) res FROM DUAL;RES
---------------------------------------------------------------- POINT (1.000000000000000 1.000000000000000)-- geometry collectionSELECT ST_AsText(ST_GeomFromGeoJSON('{"type":"GeometryCollection","geometries":[{"type":"Point","coordinates":[100.0,0.0]},{"type":"LineString","coordinates":[[101.0,0.0],[102.0,1.0]]}],"crs":{"type":"name","properties":{"name":"urn:ogc:def:crs:EPSG::3395"}}}')) res FROM DUAL;RES
---------------------------------------------------------------- GEOMETRYCOLLECTION (POINT (100.000000000000000 0.000000000000000), LINESTRING (101.000000000000000 0.000000000000000, 102.000000000000000 1.000000000000000))