model: AMD Athlon(tm) 64 X2 Dual Core Processor 4200+打印机连接[216143.260035] usb 2-7: reset high-speed USB device number 8 using ehci_hcd[216219.096159] usb 2-7: USB disconnect,
使用group查询来计算每个feed_id的记录数,可以很容易地显示最流行的提要。但我想要计算动量,以显示大多数趋势提要。of subscriptions with created_at in past day) + 1 * (count of subscriptions with created_at from 7-28 days ago)
如何在单个(我的)SQL查询中完成这样的操作,而不是使用3