SELECT
month,
day,
COUNT(DISTINCT cookieid) AS uv,
GROUPING__ID
FROM user_date
GROUP BY month,day...上述SQL等价于:
SELECT NULL,NULL,COUNT(DISTINCT cookieid) AS uv,0 AS GROUPING__ID FROM user_date
UNION ALL...SELECT month,NULL,COUNT(DISTINCT cookieid) AS uv,1 AS GROUPING__ID FROM user_date GROUP BY month...UNION ALL
SELECT NULL,day,COUNT(DISTINCT cookieid) AS uv,2 AS GROUPING__ID FROM user_date GROUP BY...ORDER BY login_date)) AS diff
FROM(SELECT DISTINCT id, login_date FROM Logins) a) b
INNER JOIN Accounts