SELECT pois.poi_id, pois.feature_code, pois.geometry, names.NAME
FROM csf_md_pois pois, csf_md_poi_nm_asgns poin, csf_md_names names
WHERE pois.poi_id = poin.poi_id
AND names.name_id = poin.name_id
AND names.admin_bound_id IS NULL
AND names.railroad_segment_id IS NULL
AND names.landuse_id IS NULL
AND names.hydrography_id IS NULL
UNION ALL
SELECT pois.poi_id, pois.feature_code, pois.geometry, NULL
FROM csf_md_pois pois, csf_md_poi_nm_asgns poin
WHERE pois.poi_id = poin.poi_id
AND NOT EXISTS (SELECT 1
FROM csf_md_names names
WHERE names.name_id = poin.name_id)