CREATE TABLE participants_in_events (event_id NUMBER, participant_id NUMBER)
CREATE TABLE events (event_id NUMBER, service_id NUMBER, event_details CLOB)
CREATE TABLE participants (participant_id NUMBER, participant_type_code CLOB, participant_details CLOB)
CREATE TABLE services (service_id NUMBER, service_type_code CLOB)

List the type of the services in alphabetical order.
SELECT service_type_code FROM services ORDER BY service_type_code
SELECT "service_type_code" FROM "services" ORDER BY "service_type_code"