Собственно работает всё.
Вот итоговый запрос:
SELECT date_format(date_insert, "%Y.%m.%d") as Date, Sum(price), AVG(price) as SrCheck
FROM b_sale_order
WHERE (canceled = 'N') AND (date_insert BETWEEN '2017.01.01' AND '2017.01.31')
GROUP BY Date
ORDER BY Date