Question

关注我之前的question。

我有一个名为activity的表，有两列：

`when` as datetime // last time i saw a user
guid as varchar  // a unique identifier for each user

我有一个查询，它返回给定日期和时间跨度的新用户数：

 SET @till_date='2009-11-01'; #for today, give CURDATE()+1
 SET @duration=1; # this can be changed to 7, 31, etc
 SELECT COUNT(guid) AS total_new_users, DATE_SUB(@till_date, INTERVAL @duration DAY) AS since_date, @till_date AS till_date
 FROM `activity` WHERE 1
  AND `when` BETWEEN DATE_SUB(@till_date, INTERVAL @duration DAY) AND @till_date
  AND guid NOT IN
  (
   SELECT guid
   FROM `activity`
   WHERE `when` < DATE_SUB(@till_date, INTERVAL @duration DAY)
  )

我希望能够构建一个查询，该查询将在给定的时间跨度内返回每个日期的新用户列表。它将用于构建一个月，一周等每天新用户的图表。

这样的事情：

total_new_users  |  since_date  |  till_date
----------------------------------------------
   10            |  2009-11-20  |  2009-11-21
   10            |  2009-11-21  |  2009-11-22
   10            |  2009-11-22  |  2009-11-23

我考虑过将UNION与LOOP一起使用，但我的SQL知识非常基础，有帮助吗？

结果（感谢@pilcrow）：

SET @till_date='2009-11-15';
SET @since_date='2009-11-01';
SELECT first AS yyyymmdd, 
   COUNT('x') AS new_user_count
FROM (SELECT guid,
             DATE(MIN(`when`)) AS first
      FROM activity
      GROUP BY 1) first_appearance
WHERE first BETWEEN @since_date AND @till_date
GROUP BY 1

Answer 1

假设 SET SESSION sql_mode ='ANSI_QUOTES'：

SELECT first AS yyyymmdd, 
       COUNT('x') AS new_user_count
FROM (SELECT guid,
             MIN("when") AS first
      FROM activity
      GROUP BY 1) first_appearance
WHERE first BETWEEN @since_date AND @till_date
GROUP BY 1

如果您愿意，您当然可以将DATE_SUB()替换为@since_date。

Answer 2

SELECT 
    COUNT(DISTINCT guid) AS total_new_users, 
    DATE(when) AS since_date, 
    DATE(DATE_ADD(when, INTERVAL 1 DAY)) AS till_date 
FROM 
    Activity 
GROUP BY 
    DATE(when)

帮助（另一个）SQL查询

2 个答案: