Get average votes for yes, month-by-month

averages.sql

select DATE_FORMAT(createdAt, "%Y-%m-01") AS month, count(choice) as votesTotal, 
	(SELECT count(choice)
	FROM survey
    WHERE choice = 'no'
    AND YEAR(createdAt) = YEAR(month) AND MONTH(createdAt) = MONTH(month)
    ) AS numNoVotes,
    (SELECT 100 - numNoVotes / count(choice) * 100) AS percentageVotedYes
from survey 
GROUP BY DATE_FORMAT(createdAt, "%Y-%m-01")