Question

我正在尝试在下表中执行查询（使用Access 2010）：

Contact   |   Facility_Contact   |   Facility   |   Bank
          |                      |              |     
ID        |   (fk) Contact_ID    |      ID      |   ID
CName     |   (fk) Facility_ID   |    FName     |   BName
          |                      |    BNumber   |   BNumber

我希望显示最终结果：

CName | FName | BName

以下是查询：

SELECT 
  HUD.[HOLDER NAME], Facility.PROVNAME, Contact.LAST_NAME

FROM 
  Facility INNER JOIN Bank ON Facility.[BNumber] = Bank.[BNumber]) INNER JOIN
  (Contact INNER JOIN Facility_Contact ON Contact.[ID] = Facility_Contact.[Contact_ID]) ON Facility.[ID] = Facility_Contact.[Facility_ID];

这不会产生任何结果。

添加“银行”表时出现问题。从联系到工厂的查询工作，以及从工厂到银行的查询。但是，当我尝试从联系人链接到银行时，我很难产生结果。

在某处可能是Where-like子句？但现在我说的是我不太熟悉的事情;）

谢谢大家！

Answer 1

FROM Facility INNER JOIN Bank ON Facility.[BNumber] = HUD.[BNumber])

你关闭了一个paranthetical但从未打开它。虽然这会导致错误，所以我认为这是一个错字。

Facility INNER JOIN Bank ON Facility.[BNumber] = HUD.[BNumber]

您正在使用Facility加入Bank，但在您的ON条款中，您声明Facility.[BNumber] = HUD.[BNumber] HUD来自哪里？这不好。

Facility INNER JOIN Bank ON Facility.[BNumber] = HUD.[BNumber]) INNER JOIN (Contact INNER JOIN Facility_Contact ON Contact.[ID] = Facility_Contact.[Contact_ID]) ON Facility.[ID] = Facility_Contact.[Facility_ID];

您的架构似乎是Facility-＆gt; Bank; Facility-＆GT; Facility_contact-＆GT;联系。考虑重写以反映这一点（这只是为了可读性）：

FROM 
    Facility 
    INNER JOIN Bank ON Facility.[BNumber] = Bank.[BNumber]
    INNER JOIN Facility_Contact ON Facility.[ID] = Facility_Contact.[Facility_ID]
    INNER JOIN Contact ON Facility_Contact.[Contact_ID] = Contact.[ID]

现在要获取记录，所有这些连接都需要包含数据。对于BNUMBER表格中的每个Bank，您的BNumber表格中需要有匹配的Facility。您facility_id中Facility_Contact表中的每个ID都需要匹配Facility。您的ID表中的每个Contact都需要在Contact_ID表格中匹配Facility_Contact。如果缺少任何这些链接，您将获得0条记录。如果您想显示Facilties和银行名称，无论他们是否有设施联系人，请考虑使用LEFT JOIN：

FROM 
    Facility 
    INNER JOIN Bank ON Facility.[BNumber] = Bank.[BNumber]
    LEFT JOIN Facility_Contact ON Facility.[ID] = Facility_Contact.[Facility_ID]
    LEFT JOIN Contact ON Contact.[ID] = Facility_Contact.[Contact_ID]

这不会因为您在设施中没有联系人而导致结果丢失。或者联系人表中尚未设置该联系人。

访问：内部联接查询不生成结果

1 个答案: