SUM在一個SQL統計查詢

Question

我有這樣的數據

time            Members 
-------------------------------------------------- ----------- 
Jun 23 2016           1 
Jun 23 2016           1 
Jun 23 2016           2 
Jun 29 2016           6 
Jul 11 2016           3 
Jul 11 2016           1 
Jul 13 2016           1 

的我用這個sql查詢

SELECT CONVERT (VARCHAR(12), a.registered_time), COUNT(b.member_id) AS Members 
FROM b 
Inner JOIN a ON b.mirror_id = a.mirror_id 
GROUP BY 
(a.registered_time) order by a.registered_time 

我想總人數的總和，如果他們獲得這種數據截止2016年6月23日的同一日期將有4名成員，等等。是否有可能在Count（）上有SUM（）函數？我怎樣才能做到這一點？

Answer 1

值轉換爲一個date幷包括在兩個select和group by：

SELECT CONVERT(date, a.registered_time) as dte, COUNT(b.member_id) AS Members 
FROM b JOIN 
    a 
    ON b.mirror_id = a.mirror_id 
GROUP BY CONVERT(date, a.registered_time) 
ORDER BY CONVERT(date, a.registered_time);