创建一周中活动天数的分布。 SQL

Question

我在SQL中有一个看起来像这样的表。

Date    CustomerID
1/1        12
1/3        32
1/3        42 
1/4        52
1/4        62  
1/5        75

我想创建一周内活动的＃天分布：创建一个表以显示在3 / 1-3 / 7的1天，2天，3天，…7天有多少成员处于活动状态。

Screenshot of desired result

我已经写了这个查询。它行得通吗？

SELECT COUNT (DISTINCT date) AS ‘#Days Active’, COUNT(DISTINCT memberID) AS ‘Count’ 
FROM User Table 
WHERE date BETWEEN ‘03/01/17’ AND 03/07/17 
GROUP by COUNT (DISTINCT date) 
ORDER BY COUNT (DISTINCT date) ASC;

Answer 1

如果我不误解您的意思，代码如下所示：这是一个两步查询：步骤1：获取每个成员的活动天数步骤2：获取每种活跃天数的会员数。

SELECT active_days, count(*) AS member_cnt
  FROM(
       SELECT CustomerID, count(*) AS active_days
         FROM your_table_name
        GROUP BY CustomerID)a
 GROUP BY active_days

Answer 2

如果我正确理解您的表，则每个客户有多行。例如，客户12在输入日期之间有一行，而客户32在输入日期之间有3行。

首先，您需要按customerId分组以获取activeDayCounts，然后按activeDays分组以对客户进行计数

select x.activeDays, count(1) count from (
  select CustomerID, count(1) activeDays from temp
  where Date between '2017-03-01' and '2017-03-07'
  group by CustomerID) x
group by x.activeDays

您可以通过链接https://dbfiddle.uk/?rdbms=sqlserver_2012&fiddle=19a3187913985faef617d9110730feba查看经典作品>