SUM of COUNT(DISTINCT date)

Question

我在使用以下 SQL 时遇到了一些困难：

SELECT SUM(mycount) 
FROM 
    (SELECT COUNT(DISTINCT `User`) AS mycount 
     FROM `DBname` 
     WHERE date(Created) >= '2016-07-01'
    ) as R ; 

目标是总结一个月内唯一条目的数量。

Answer 1

SELECT SUM(mycount) 
FROM  (
    SELECT COUNT(DISTINCT `User`) AS mycount 
    FROM DBname 
    WHERE date(Created) >= '2016-07-01'
    GROUP BY date(Created)
) as R ;