Question

抱歉，我之前发过一个类似的问题，但我不是那么清楚。我有一个表，其中包含Customer，ID_Date，Pstng_Date，SUMOfAmount，Days_BetweenMax和days_between Min。

我想要的是一个查询，它显示pstng_date和ID_Date之间的日期差异，其中pstng_date是该客户的最大值，另一列显示相同的计算，其中pstng_date是该客户的最小值。只有一个Pstng_date的客户应显示为零

所以Query应该显示如下结果：

Customer ID_Date    Pstng_Date SumOfAmount Days_BetweenMAX days_betweenMIN
-------- ---------- ---------- ----------- ------------
Holmes   31/01/2014 10/01/2014  $21,545.59            0       0
James    31/01/2014 10/01/2014 -$21,197.89            0       21
James    31/01/2014  5/01/2014  -$7,823.14            0       0
James    31/01/2014 24/01/2014     $308.00            7       0
Rod      31/01/2014 17/01/2014  -$2,603.95            0       0
Lisa     31/01/2014 17/01/2014  $22,019.49            0       0

Answer 1

假设您的现有表名为[Postings]，您可以创建一个查询来计算[Pstng_Date]的MIN（）和MAX（）值

SELECT
    Customer,
    MIN(Pstng_Date) AS MinOfPstng_Date,
    MAX(Pstng_Date) AS MaxOfPstng_Date
FROM Postings
GROUP BY Customer

返回

Customer  MinOfPstng_Date  MaxOfPstng_Date
--------  ---------------  ---------------
Holmes    2014-01-10       2014-01-10     
James     2014-01-05       2014-01-24     
Lisa      2014-01-17       2014-01-17     
Rod       2014-01-17       2014-01-17

然后，您可以将其用作查询中的子查询来计算日期差异

SELECT
    p.Customer,
    p.ID_Date,
    p.Pstng_Date,
    p.SumOfAmount,
    IIf(q.MaxOfPstng_Date=q.MinOfPstng_Date,0,IIf(p.Pstng_Date=q.MaxOfPstng_Date,DateDiff("d",p.Pstng_Date,p.ID_Date),0)) AS Days_BetweenMAX,
    IIf(q.MaxOfPstng_Date=q.MinOfPstng_Date,0,IIf(p.Pstng_Date=q.MinOfPstng_Date,DateDiff("d",p.Pstng_Date,p.ID_Date),0)) AS Days_BetweenMIN
FROM
    Postings AS p
    INNER JOIN
    (
        SELECT
            Customer,
            MIN(Pstng_Date) AS MinOfPstng_Date,
            MAX(Pstng_Date) AS MaxOfPstng_Date
        FROM Postings
        GROUP BY Customer
    ) AS q
        ON p.Customer = q.Customer

返回

Customer  ID_Date     Pstng_Date  SumOfAmount  Days_BetweenMAX  Days_BetweenMIN
--------  ----------  ----------  -----------  ---------------  ---------------
Holmes    2014-01-31  2014-01-10     21545.59                0                0
James     2014-01-31  2014-01-10    -21197.89                0                0
James     2014-01-31  2014-01-05     -7823.14                0               26
James     2014-01-31  2014-01-24       308.00                7                0
Rod       2014-01-31  2014-01-17     -2603.95                0                0
Lisa      2014-01-31  2014-01-17     22019.49                0                0

基于MAX和MIN值的完整日期计算

1 个答案: