Question

我正在使用ms-access，我有2个表tblAssets和tblauditlog，我试图获取资产状态为6（表示已出售）的所有资产的最新审计日志。这两个表之间的关系是tblassets.assetid = tblauditlog.logaspectid，我只获得了已售出资产的所有审核日志，但我正在寻找最后一条记录。我有一个日期字段，但是当我使用Max（tblauditlog.logtimestamp）时会抛出错误

我尝试使用

SELECT <br>
r.assetid, <br>
r.assetcategory, <br>
r.assetstatus, <br>
sub2.logmessage, <br>
sub2.logtimestamp <br>
FROM <br>
     tblAssets as r <br>
LEFT JOIN <br> <br>
 (SELECT <br>
     sub1.logaspectid, <br>
     a2.logMessage, <br>
     a2.logtimestamp <br>
 FROM  <br>
       ( <br>
        SELECT <br>
         a1.logaspectid, <br>
         Max(a1,logtimestamp) AS MaxOfTimeStamp <br>
         FROM tblauditlog AS a1  <br>
         GROUP BY a1.logaspectid ) AS sub1  <br>
       INNER JOIN tblauditlog as a2  <br>
 ON  <br>
     (sub1.MaxOfTimeStamp = a2.logTimestamp) AND (sub1.logaspectid = a2.logaspectid)) AS sub2 <br>
ON r.assetid = sub2.logaspectid ;

上面给我一个错误：

无法执行查询。使用多值的无效操作或语法字段

这就是我要返回的多条记录

SELECT tblAssets.assetID, tblAssets.assetCategory, tblAssets.assetModel,
       tblAssets.assetStatus, tblAuditLog.logAspectID, tblAuditLog.logMessage,
       tblAuditLog.logTimeStamp
FROM tblAssets
    LEFT JOIN tblAuditLog ON tblAssets.assetID = tblAuditLog.logAspectID
WHERE (((tblAssets.assetStatus)=6)
   AND ((tblAuditLog.logTimeStamp)>=#1/1/2017#));

我只想出售所有资产状态= 6的最后记录的日志。

Answer 1

如果我理解正确，则可以使用相关的子查询来获取最新的审核日志记录。然后，您可以检查其是否具有所需的状态：

SELECT . . .
FROM tblAssets as a INNER JOIN
     tblauditlog as al
     ON a.assetid = al.logaspectid
WHERE al.logtimestamp = (SELECT MAX(al2.logtimestamp)
                         FROM tblauditlog as al2
                         WHERE al2.logaspectid = al.logaspectid
                        ) AND
      al.assetstatus = 6 ;

选择一对多关系中的最后一条记录

1 个答案: