What is the difference of 10 stars votes between the first episode and the last episode?
the first episode refers to episode = 1; the last episode refers to episode = 24; 10 stars vote refers to stars = 10; the difference = subtract(votes where episode = 1, votes where episode = 24) where stars = 10
SELECT SUM(CASE WHEN T2.episode = 24 THEN T1.votes ELSE 0 END) - SUM(CASE WHEN T2.episode = 1 THEN T1.votes ELSE 0 END) FROM Vote AS T1 INNER JOIN Episode AS T2 ON T2.episode_id = T1.episode_id WHERE T1.stars = 10