IIF功能（访问）

Question

任何访问专家的外面，可以帮助我吗？试图找出如何实现以下内容：我想要一个查询遍历个人表中的每个人，并返回在圣诞节列表字段中具有真实价值的人。这个数据库是旧的，是用CompanyName作为公司表的主键创建的（我知道 - 糟糕的设计）。为了避开拥有多个地点的公司，他们创建了一个地址栏。这样，如果“公司y”在圣地亚哥开设了新的位置，他们添加了“Y公司 - 圣地亚哥”的条目，并在地址栏中输入“Y公司”。然后，对于没有公司的个人，他们被输入“家庭”的虚拟公司条目。所以理想情况下，我想要这个查询做的是循环，抓住所有应该在圣诞节列表中的个人。如果地址栏字段不为空，我希望CompanyName等于AddressLine，但是如果CompanyName =“首页“我希望公司名称等于”“（emptry字符串）。也有些人有通宵地址，因为他们的普通地址是P.O Box。下面的查询我主要为我工作，但是我不清楚如何使CompanyName =“Home”中的公司名在返回的结果中留空。

SELECT tblIndividuals.FirstName, tblIndividuals.LastName, IIf([tblcompanies].[addressline] Is Not Null,[tblcompanies].[addressline],[tblcompanies].[companyname]) AS CompanyName, IIf([tblIndividuals].[MailingAddress1] Is Null,[tblCompanies].[MailingAddress1],[tblIndividuals].[MailingAddress1]) AS MailingAddress1, IIf([tblIndividuals].[MailingAddress1] Is Null,[tblCompanies].[MailingAddress2],[tblIndividuals].[MailingAddress2]) AS MailingAddress2, IIf([tblIndividuals].[MailingAddress1] Is Null,[tblCompanies].[MailingAddress3],[tblIndividuals].[MailingAddress3]) AS MailingAddress3, IIf([tblIndividuals].[MailingAddress1] Is Null,[tblCompanies].[MailingAddress4],[tblIndividuals].[MailingAddress4]) AS MailingAddress4, IIf([tblIndividuals].[MailingAddress1] Is Null,[tblCompanies].[City],[tblIndividuals].[City]) AS City, IIf([tblIndividuals].[MailingAddress1] Is Null,[tblCompanies].[State],[tblIndividuals].[State]) AS State, IIf([tblIndividuals].[MailingAddress1] Is Null,[tblCompanies].[Zip],[tblIndividuals].[Zip]) AS Zip 
FROM tblIndividuals INNER JOIN tblCompanies ON tblIndividuals.CompanyName = tblCompanies.CompanyName 
WHERE (((tblIndividuals.ChristmasList)=True)) 
Order by [tblIndividuals].[companyname]; 

我很想排序公司名称值（A-Z）拥有它，然后如果在所有可能的个人的姓氏（A-Z）。我不会假装对SQL很好，所以你可以给我的任何帮助将非常感激。感谢您的时间。

Answer 1

考虑一个UNION查询，例如：

SELECT i.FirstName, i.LastName, 
     IIf(c.[addressline] Is Not Null, 
      c.[addressline],c.[companyname]) AS CompanyName, 
     c.[MailingAddress1] AS MailingAddress1, 
     c.[MailingAddress2] AS MailingAddress2, 
     c.[MailingAddress3] AS MailingAddress3, 
     c.[MailingAddress4] AS MailingAddress4, 
     c.[City] AS City, 
     c.[State] AS State, 
     c.[Zip] AS Zip 
FROM tblIndividuals i 
INNER JOIN tblCompanies c ON i.CompanyName = c.CompanyName 
WHERE i.ChristmasList=True 
AND i.[MailingAddress1] Is Null 
UNION 
SELECT i.FirstName, i.LastName, 
     IIf(c.[addressline] Is Not Null,c.[addressline], 
      c.[companyname]) AS CompanyName, 
     i.[MailingAddress1] AS MailingAddress1, 
     i.[MailingAddress2] AS MailingAddress2, 
     i.[MailingAddress3] AS MailingAddress3, 
     i.[MailingAddress4] AS MailingAddress4, 
     i.[City] AS City, 
     i.[State] AS State, 
     i.[Zip] AS Zip 
FROM tblIndividuals i 
INNER JOIN tblCompanies c ON i.CompanyName = c.CompanyName 
WHERE i.ChristmasList=True 
AND i.[MailingAddress1] Is Not Null 

你可以用查询括号创建一个派生表，您可以使用排序查询设计窗口。

SELECT FirstName, LastName, etc 
FROM (<union query>) As q 
Order by q.[companyname]