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 broadcast (channel_id NUMBER, program_id NUMBER, time_of_day CLOB)
CREATE TABLE program (program_id NUMBER, name CLOB, origin CLOB, launch NUMBER, owner CLOB)

find the total percentage share of all channels owned by CCTV.
SELECT SUM(share_in_percent) FROM channel WHERE owner = 'CCTV'
SELECT SUM("share_in_percent") FROM "channel" WHERE "owner" = 'CCTV'