CREATE OR REPLACE FUNCTION poi_class(subclass TEXT)
RETURNS TEXT AS $$
    SELECT CASE
        WHEN subclass IN ('accessories','antiques','art','beauty','bed','boutique','camera','carpet','charity','chemist','chocolate','coffee','computer','confectionery','convenience','copyshop','cosmetics','garden_centre','doityourself','erotic','electronics','fabric','florist','furniture','video_games','video','general','gift','hardware','hearing_aids','hifi','ice_cream','interior_decoration','jewelry','kiosk','lamps','mall','massage','motorcycle','mobile_phone','newsagent','optician','outdoor','perfumery','perfume','pet','photo','second_hand','shoes','sports','stationery','tailor','tattoo','ticket','tobacco','toys','travel_agency','watches','weapons','wholesale') THEN 'shop'
        WHEN subclass IN ('townhall','public_building','courthouse','community_centre') THEN 'town_hall'
        WHEN subclass IN ('golf','golf_course','miniature_golf') THEN 'golf'
        WHEN subclass IN ('fast_food','food_court') THEN 'fast_food'
        WHEN subclass IN ('park','bbq') THEN 'park'
        WHEN subclass IN ('bus_stop','bus_station') THEN 'bus'
        WHEN subclass IN ('camp_site','caravan_site') THEN 'campsite'
        WHEN subclass IN ('laundry','dry_cleaning') THEN 'laundry'
        WHEN subclass IN ('supermarket','deli','delicatessen','department_store','greengrocer','marketplace') THEN 'grocery'
        WHEN subclass IN ('books','library') THEN 'library'
        WHEN subclass IN ('university','college') THEN 'college'
        WHEN subclass IN ('hotel','motel','bed_and_breakfast','guest_house','hostel','chalet','alpine_hut','camp_site') THEN 'lodging'
        WHEN subclass IN ('chocolate','confectionery') THEN 'ice_cream'
        WHEN subclass IN ('post_box','post_office') THEN 'post'
        WHEN subclass IN ('cafe') THEN 'cafe'
        WHEN subclass IN ('school','kindergarten') THEN 'school'
        WHEN subclass IN ('alcohol','beverages','wine') THEN 'alcohol_shop'
        WHEN subclass IN ('bar','nightclub') THEN 'bar'
        WHEN subclass IN ('marina','dock') THEN 'harbor'
        WHEN subclass IN ('car','car_repair','taxi') THEN 'car'
        WHEN subclass IN ('hospital','nursing_home') THEN 'hospital'
        WHEN subclass IN ('grave_yard','cemetery') THEN 'cemetery'
        WHEN subclass IN ('attraction','viewpoint') THEN 'attraction'
        WHEN subclass IN ('biergarten','pub') THEN 'beer'
        WHEN subclass IN ('music','musical_instrument') THEN 'music'
        WHEN subclass IN ('american_football','stadium','soccer','pitch') THEN 'stadium'
        WHEN subclass IN ('accessories','antiques','art','artwork','gallery','arts_centre') THEN 'art_gallery'
        WHEN subclass IN ('bag','clothes') THEN 'clothing_store'
        WHEN subclass IN ('swimming_area','swimming') THEN 'swimming'
        ELSE subclass
    END;
$$ LANGUAGE SQL IMMUTABLE;