Question: find the program owners that have some programs in both morning and night time.
Schema: create table broadcast (program_id varchar, time_of_day varchar, PRIMARY KEY (program_id)); create table program (owner varchar, program_id varchar, PRIMARY KEY (owner))
SQL: select t1.owner from program as t1 join broadcast as t2 on t1.program_id = t2.program_id where t2.time_of_day = "morning" intersect select t1.owner from program as t1 join broadcast as t2 on t1.program_id = t2.program_id where t2.time_of_day = "night"