3 表连接的 MS Access VB SQL 语法

Question

我一直在尝试创建一个包含来自 3 个表的信息的表单。 在这个表单上，我想要一个过滤器组合框，以便用户可以选择一个成员类型，它会将列表过滤为具有该成员类型的成员。

我们数据库中的成员可以有多种类型。 为此，我创建了一个成员表：

MemberID FName SName 等

成员类型表：

MemberTypeID MemberTypeName

和一个连接表成员成员类型：

会员ID 会员类型ID

我试图用许多不同的查询来设置我的表单：

SELECT qryMemberType.MemberID, qryMemberType.FName, qryMemberType.SName, 
qryMemberType.MemberTypeName, qryMemberType.MemberTypeID FROM qryMemberType;

SELECT [member].[MemberID] AS [member_MemberID], [member].[FName], [member].[SName], 
[membertype].[MemberTypeID] AS [membertype_MemberTypeID], [membertype].[MemberTypeName], 
[membermembertype].[MemberID] AS [membermembertype_MemberID], [membermembertype].[MemberTypeID] 

SELECT [member].[MemberID] AS [member_MemberID], [member].[FName], [member].[SName], 
[membermembertype].[MemberID] AS [membermembertype_MemberID], 
[membermembertype].[MemberTypeID] AS [membermembertype_MemberTypeID], 
[membertype].[MemberTypeID] AS [membertype_MemberTypeID]

我一直试图过滤的组合框的 VBA 是：

Dim myMember As String
    
    myMember = "SELECT ... FROM ... WHERE ([MemberTypeID] = " & Me.cboMemberType & ");"
    Me.frmFilterTestSub.Form.RecordSource = myMember
    Me.frmFilterTestSub.Form.Requery

我为组合框的 VBA 中的 SELECT 语句尝试了多种不同的语法，包括：

"Select * from membermembertype where ([MemberTypeID] = " & Me.cboMemberType & ")"

"SELECT member.MemberID AS member_memberID, member.FName, member.SName, 
        membertype.MemberTypeID AS membertype_MemberTypeID, membertype.MemberTypeName, 
        membermembertype.MemberID AS membermembertype_MemberID, 
        membermembertype.MemberTypeID AS membermembertype_MemberTypeID 
    FROM member 
    LEFT JOIN (membertype 
    RIGHT JOIN membermembertype ON membertype.[MemberTypeID] = membermembertype.[MemberTypeID])
        ON member.[MemberID] = membermembertype.[MemberID] 
    WHERE ([MemberTypeID] = " & Me.cboMemberType & ")"

"SELECT member.*, 
        (membermembertype.MemberID AS mmt_MemberID), 
        (membermembertype.MemberTypeID AS mmt_MemberTypeID), 
        membertype.MemberTypeName 
    FROM (member 
    LEFT JOIN membermembertype ON mmt_MemberID = (member.MemberID AS m_MemberID)) 
    RIGHT JOIN membertype ON mmt_MemberTypeID=(membertype.MemberTypeID AS mt_MemberTypeID) 
    WHERE ([MemberTypeID] = " & Me.cboMemberType & ");"

我很确定第一个示例返回最接近的结果，列表返回每个所选成员类型的正确记录数，但是字段填充了#Name？ 错误值，这就是为什么我试图用多种不同的方式来连接表。 其他 SELECT STATEMENTS 返回 SQL 语法错误。

任何建议将不胜感激！

Answer 1

当您可以按正确顺序使用左外连接时，右外连接在 SQL 中非常不受欢迎。

在您的情况下，无论如何内部联接更好。

如果您关心安全性，您应该使用参数而不是字符串连接，但是由于您使用的是 Access，我猜任何有权访问该文件的人都可以做他们喜欢的事情。

请尝试此方法，如果出现错误，请告诉我。

SELECT [Member].MemberId
, [Member].FName
, [Member].SName
, [MemberType].MemberTypeId
, [MemberType].MemberTypeName

FROM ((MemberType
INNER JOIN MemberMemberType ON MemberMemberType.MemberTypeId = MemberType.MemberTypeId)
INNER JOIN Member ON Member.MemberId = MemberMemberType.MemberId)

WHERE MemberType.MemberTypeId = 123 --Put your parameter here once you've tested that it works for a specific value

Answer 2

由于您只想列出成员，我猜您对成员类型表信息并不真正感兴趣，那么您可以简单地执行以下操作：

"SELECT member.MemberID AS member_memberID, member.FName, member.SName
 FROM member 
 INNER JOIN membermembertype 
   ON (membermembertype.[MemberTypeID] = " & Me.cboMemberType & " AND member.[MemberID]=membermembertype.[MemberID]) "