What is the average duration of the blues songs?
select avg(t1.duration) from files as t1 join song as t2 on t1.f_id = t2.f_id where t2.genre_is = "blues"
How about that of pop songs?
select avg(t1.duration) from files as t1 join song as t2 on t1.f_id = t2.f_id where t2.genre_is = "pop"
What about the duration, file size and format of those songs, order the results by title?
select t1.duration, t1.file_size, t1.formats from files as t1 join song as t2 on t1.f_id = t2.f_id where t2.genre_is = "pop" order by t2.song_name