MS 访问计数不同的多列

Posted 2023-04-19

【中文标题】MS 访问计数不同的多列

【英文标题】：MS Access Count Distinct Multiple Columns

【发布时间】：2018-02-23 20:23:50

【问题描述】：

我一直在尝试使用 Count distinct 编写基于 SQL 的查询，但遇到了如何正确构建 Microsoft Access 格式的问题。

我当前的查询格式如下，如果可能的话，我想将 Count 操作转换为 distinct count：

SELECT 
a.Customer_ID, a.First_Name,
COUNT (b.Payment_Method) AS Payment_Method <- would like to get the distinct count
Count (b.Store_Number) as Store_Number     <- would like to get the distinct count
SUM (b.Sales_Amount) AS Sales_Amount 
FROM Table1 a
INNER JOIN Table2 b ON a.Customer_ID = b.Customer_ID
WHERE (((a.Date_ID) > 1234))
GROUP BY a.Customer_ID, a.First_Name

我熟悉此查询的 SQL 构造，并希望使用 MS-Access 重新创建结果。

【问题讨论】：

必须首先构建一个返回 Distinct 记录的查询。然后在另一个查询中使用该查询来计算这些记录。

***.com/questions/11880199/…

【参考方案1】：

这比其他数据库复杂得多，但你可以在加入之前：

SELECT a.Customer_ID, a.First_Name, p.num_pm, s.num_sn, s.sum_sa
FROM (Table1 as a INNER JOIN
      (SELECT CustomerId, COUNT(*) as num_pm
       FROM (SELECT DISTINCT CustomerId, Payment_Method FROM Table2) as b
       GROUP BY CustomerId
      ) as p
      ON a.CustomerId = p.CustomerId
     ) INNER JOIN
     (SELECT CustomerId, COUNT(*) as num_sn, SUM(sa) as sum_sa
      FROM (SELECT CustomerId, Store_Number, SUM(Sales_Amount) as sum_sa
            FROM Table2
            GROUP BY CustomerId, Store_Number
           ) as b
      GROUP BY CustomerId
     ) as s
     ON s.CustomerId = a.CustomerId
WHERE a.Date_ID > 1234