Question

我很难为每个用户返回多个值。我尝试过Select Distinct的变种无济于事。我需要我的代码只返回每个userID一个值。

SELECT Roster.UserID, 
    EventLog.Type, 
    IIf([EventLog]![LogType] Like "Acc*" And [EventLog]![Action] Like "Wri*",[EventLog]![Date],Date()-183) AS [Review Date]
FROM EventLog 
INNER JOIN Roster 
    ON EventLog.UserID = Roster.UserID
GROUP BY Roster.UserID, 
    EventLog.Type, 
    IIf([EventLog]![LogType] Like "Acc*" And [EventLog]![Action] Like "Wri*",[EventLog]![Date],Date()-183)
HAVING (((EventLog.Type) Like "Att*"));

代码在满足第一个条件时从IIf返回两个值。我怎么能限制一个或另一个？

Answer 1

您为每个用户获取了多个值，因为您在GROUP BY子句中列出了多个字段：

    GROUP BY Roster.UserID, 
        EventLog.Type, 
        IIf([EventLog]![LogType] Like "Acc*" And 
[EventLog]![Action] Like "Wri*",[EventLog]![Date],Date()-183)

我不确定你为什么要分组，因为你没有执行任何聚合功能。 SELECT DISTINCT会有效吗？

Answer 2

感谢您的反馈意见。基于Beth回复并清理我的表格和查询以发送dBase的副本，问题似乎通过一小部分代码自行解决。

SELECT Roster.UserID, 
EventLog.Type, 
Max(IIf(EventLog!LogType Like "Acc*" And EventLog!Action Like "Wri*",EventLog!Date,Date()-183)) AS [Review Date]
FROM EventLog 
INNER JOIN Roster 
ON EventLog.UserID = Roster.UserID
GROUP BY Roster.UserID,
EventLog.Type
HAVING (((EventLog.Type) Like "Att*"));

Beth对多场的清理工作得很好!!!

Access 2003查询困境

2 个答案: