ms-access - 在运行 vba 表达式之前检查结果是否在查询中

Question

在 MS Access 2010 数据库中，我有一个导航子表单，其中包含一些文本框，其值是从基础查询中填充的，以及一个计算的文本框。我想在计算的文本框中添加一些条件逻辑。

其中两个填充的文本框是 ClientNumber 和 DOB。在表达式生成器中，计算的文本框是 Age，当前计算如下：

=DateDiff("yyyy",[DOB],Now())+Int(Format(Now(),"mmdd")<Format([DOB],"mmdd"))  

我想将年龄计算更改为类似于以下伪代码：

=IiF( 
    ClientNumber IN qryActiveClients, 
    DateDiff("yyyy",[DOB],Now())+Int(Format(Now(),"mmdd")<Format([DOB],"mmdd"))  ,
     "NA"
    )

有人可以告诉我如何更改此伪代码，使其成为完成所需任务的实际工作代码吗？

作为参考，qryActiveClients 如下：

SELECT DISTINCT 
    ActiveCustomers.FirstName, 
    ActiveCustomers.LastName, 
    tblClientAddress.HomePhone, 
    ActiveCustomers.ClientNumber
FROM 
    (
        SELECT 
            Clients.ClientNumber, 
            Clients.FirstName, 
            Clients.LastName, 
            (         
                SELECT COUNT(ReferralDate) FROM IntakeTable              
                WHERE Clients.ClientNumber =  IntakeTable.ClientNumber 
                AND Len(ReferralDate & '') > 0 
            ) AS IntakeCount, 
            (         
                SELECT COUNT(ExitDate) FROM ExitTable              
                WHERE  Clients.ClientNumber = ExitTable.ClientNumber 
                AND Len(ExitDate & '') > 0            
            ) AS ExitCount FROM Clients
    )  AS ActiveCustomers 
    INNER JOIN tblClientAddress 
    ON ActiveCustomers.ClientNumber = tblClientAddress.ClientNumber
    WHERE (((ActiveCustomers.IntakeCount)>[ExitCount]) AND ((tblClientAddress.CurrentResidence)=True));

请注意，qryActiveClients 与填充其他控件的查询不同。

Answer 1

I believe you're looking for something like this:

=IIf( 
    DCount("*", "qryActiveClients", "ClientNumber=" & [ClientNumber]) > 0, 
    DateDiff("yyyy",[DOB],Now())+Int(Format(Now(),"mmdd")<Format([DOB],"mmdd")),
    "NA"
    )