Question

我需要加入3个数据表才能生成一个表并显示以下字段： u.master_id，p.surname，p.forename1，c.number，u.status

以下是表格详情：

Table 1 (person p)
Field name = entity_id (number)
Field name = surname(text)
Field name = forename1(text)
Field name = auditflag

Table 2 (users u)
Field name = master_id (number)
Field name = email (number)
Field name = status (text)
Field name = auditflag

Table 3 (contact c)
Field name = master_id (number)
Field name = entity_id (number)
Field name = number  (text = holds the actual email address)
Field name = auditflag

表2和3中的master_id字段链接到人entity_id（master_id = p.entity_id）

表2中的电子邮件字段链接到表3中的entity_id（u.email = c.entity_id）以获取数字

auditflag用于将每个标记标记为活动记录，即（p.auditflag = 1 AND u.auditflag = 1 AND c.auditflag = 1）

我正在使用Excel 2010 VBA - 加入PostGreSQL数据库以获取数据。下面是我用来加入2个表的代码，但是我的问题是＆＃34; email＆＃34;仅显示一个数字，因为实际地址位于名为＆＃34; number＆＃34;的字段下的第3个表（联系人）中。

我不知道如何包含第3个表格以在我的查询中显示字段c.number。

Const sqlconnection = "Provider=oledb;"

Dim conn As New Connection
    conn.ConnectionString = sqlconnection
    conn.Open

Dim rs As Recordset

Dim prs As String
    prs = "SELECT u.master_id, p.surname, p.forename1, u.email, u.status " _
    & "FROM users u INNER JOIN person p ON u.master_id=p.entity_id " _
    & "WHERE u.auditflag=1 AND p.auditflag=1 " _
    & "ORDER BY u.master_id "

Set rs = conn.Execute(prs)
With ActiveSheet.QueryTables.Add(Connection:=rs, Destination:=Range("A1"))
    .Refresh
End With

Answer 1

你拥有所有的作品;您需要做的就是将第三个表添加到查询中并选择所需的列。

Dim prs As String
    prs = "SELECT u.master_id, p.surname, p.forename1, c.number as email, u.status " _
        & "FROM users u INNER JOIN person p ON u.master_id=p.entity_id " _
        & "    INNER JOIN contact c ON c.master_id=p.entity_id and u.email=c.entity_id " _
        & "WHERE u.auditflag=1 AND p.auditflag=1 AND c.auditflag=1 " _
        & "ORDER BY u.master_id "

正如所写，此查询仅会获得具有有效（auditflag=1）person行和有效contact行的用户。更改为左连接并将auditflag检查移动到连接条件将允许返回所有三个表中没有活动行的用户。

作为旁注，我发现表格中的列名正在积极地反对，以便轻易理解它们的含义;如果可以，我建议重新考虑你正在使用的名字。

来自3个表

1 个答案: