cameras that have a 4:3 ratio and weigh less than 311.0 have what compression format?
(AND digicams.camera_compressed_format (JOIN (R digicams.digital_camera.compressed_formats) (AND (le digicams.digital_camera.weight 311.0^^http://www.w3.org/2001/XMLSchema#float) (JOIN (R digicams.camera_image_ratio.cameras) m.0220vcv))))