Question

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

我当前的查询采用以下格式，如果可能，我想将Count操作转换为非重复计数：

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。

Answer 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

MS Access Count不同的多列

1 个答案: