-- Determine the total number of purchases for each of the last ten days. List the date, as well as the total number of purchases.

-- Expected Heading: RELATION {time INTEGER, cnt INTEGER}
-- How do you treat the default case as showed in the instructions?

SELECT time, COUNT(*) AS cnt
FROM Purchases
where time > date((SELECT MAX(time) FROM Purchases),'-10 days')
GROUP BY time
;
