如何在MS Access查詢中為每個“人”每個日期選擇一個帶有內部聯接的記錄？

Question

我需要從兩個表中提取數據： Neptune_FN_Analysis和Neptune_prem將有3個字段，分別稱為readings_miu_id （與人員名稱或項目編號相對應）， ReadDate和ReadTime （所有這些都在Neptune_FN_Analysis ）。 一些readings_miu_id連續幾天有多個ReadTime ，但是我只想拉每天每天每個readings_miu_id輸入的“上次時間”。
我需要所有的readings_miu_id都具有選定范圍的輸入日期，但是只有我要提取的每個記錄都輸入了最后一個ReadTime 。

到目前為止，基於一張表的解決方案是：

SELECT readings_miu_id, Reading, ReadDate, ReadTime, MIUwindow, SN, Noise, RSSI, OriginCol, ColID, Ownage
FROM analyzed AS A
WHERE ReadDate Between #4/21/2009# and #4/29/2009# 
AND ReadTime=
    (SELECT TOP 1 analyzed.ReadTime FROM analyzed 
    where analyzed.readings_miu_id = A.readings_miu_id 
    AND analyzed.ReadDate = A.ReadDate
    ORDER BY analyzed.ReadTime DESC);

當我嘗試采用此解決方案時，無法將FROM [tableName] as A, INNER JOIN因為它給我一個錯誤。 我的前任制作的原始代碼（這是我要調整/修復的代碼）如下：

SELECT readings_miu_id, Reading, ReadDate,Format([MIUtime],'hh:mm:ss') AS 
ReadTime, MIUwindow, SN, Noise, RSSI, ColRSSI, MIURSSI, Firmware, CFGDate, FreqCorr, 
Active, MeterType, OriginCol, ColID, Ownage, SiteID, PremID, Neptune_prem.prem_group1, 
Neptune_prem.prem_group2, ReadID 
INTO analyzed  
FROM Neptune_FN_Analysis INNER JOIN 
Neptune_prem ON Neptune_FN_Analysis.PremID = Neptune_prem.premice_id 
WHERE  SiteID = 36801 and ReadDate BETWEEN #04/21/09# AND #04/27/09#  
and OriginCol = 'US 29'    and ColID = 1 and ColID <> 0 and Active = 'Y'

Answer 1

我不太了解您要執行的所有操作，但是如果您在子查詢上進行內部聯接，而該子查詢獲得了日期的最大值，則它可以消除日期不是最大值的所有記錄

SELECT readings_miu_id, Reading, ReadDate, ReadTime, MIUwindow, SN, 
Noise, RSSI, OriginCol, ColID, Ownage 
FROM analyzed 
INNER JOIN 
(SELECT [whatever the id common to all like records is] as likeID, MAX(analyzed.ReadTime) as latestDate
 FROM analyzed 
 GROUP BY likeID) AS maxDate ON analyzed.likeID=maxDate.likeID AND analyzed.latestDate = maxDate.latestDate
WHERE ReadDate Between #4/21/2009# and #4/29/2009# 

根據需要修改

Answer 2

我會嘗試這樣的事情：

SELECT a.readings_miu_id, a.Reading, a.ReadDate, a.ReadTime, a.MIUwindow, a.SN, a.Noise, a.RSSI, a.OriginCol, a.ColID, a.Ownage
FROM analyzed AS A INNER JOIN
          (SELECT max(ReadTime) as MaxReadTime,readings_miu_id FROM analyzed 
             WHERE ReadDate Between #4/21/2009# and #4/29/2009#
              GROUP BY readings_miu_id) as B 
             on a.readings_miu_id = b.readings_miu_id  and a.MaxReadTime = b.ReadTime

Answer 3

SELECT
     <your columns>
FROM
     Neptune_FN_Analysis A1
INNER JOIN Neptune_prem ON
     P.premice_id = A1.PremID
LEFT OUTER JOIN Neptune_FN_Analysis A2 ON
     A2.readings_miu_id = A1.readings_miu_id AND
     A2.ReadDate = A1.ReadDate AND
     A2.ReadTime > A1.ReadTime
WHERE
     A2.readings_miu_id IS NULL AND
     <add any additional criteria here>

Answer 4

我不確定這次指定“ INNER JOIN ”意味着什么。 其他答案使用子查詢，因此這是一個使用兩個INNER JOIN且沒有子查詢的示例。 而不是讓您的腦袋繞開您的模式:)我正在使用Northwind返回客戶及其最近訂單的日期：

SELECT C1.CustomerID, C1.CompanyName, 
       O1.OrderID, O1.OrderDate
  FROM (Customers AS C1
       INNER JOIN Orders AS O1
          ON C1.CustomerID = O1.CustomerID)
       INNER JOIN Orders AS O2
          ON C1.CustomerID = O2.CustomerID
 GROUP 
    BY C1.CustomerID, C1.CompanyName, 
       O1.OrderID, O1.OrderDate
HAVING O1.OrderDate = MAX(O2.OrderDate);