CREATE TABLE broadcast (channel_id NUMBER, program_id NUMBER, time_of_day CLOB)
CREATE TABLE broadcast_share (channel_id NUMBER, program_id NUMBER, date CLOB, share_in_percent NUMBER)
CREATE TABLE channel (channel_id NUMBER, name CLOB, owner CLOB, share_in_percent NUMBER, rating_in_percent NUMBER)
CREATE TABLE program (program_id NUMBER, name CLOB, origin CLOB, launch NUMBER, owner CLOB)

how many programs are broadcast in each time section of the day?
SELECT COUNT(*), time_of_day FROM broadcast GROUP BY time_of_day
SELECT COUNT(*), "time_of_day" FROM "broadcast" GROUP BY "time_of_day"