字符串 转 时间戳 unix_timestamp('2018-07-01 0:0:0')
SELECT FROM_UNIXTIME(createtime,'%Y%m%d') AS d, s.app,SUM(o.val) FROM orders o LEFT JOIN app_type s ON o.app_id=s.app_id
WHERE o.type_id IN (1,8,12) AND createtime>=unix_timestamp('2018-07-01 0:0:0')
GROUP BY d, o.app_id ORDER BY o.app_id ASC,FROM_UNIXTIME(createtime,'%Y%m') DESC,d DESC;