Question

刚开始尝试使用JOIN子句，这样我就可以在gridview中显示多个表中的数据。但是，我不能为我的生活弄清楚我的错误在这里。我试过切换调用的表的顺序，调用的列，这样就没有成功。我认为，这是最接近工作的我能得到的陈述。它基本上是一个所谓的工作声明的直接副本，但仍然无法正常工作。

感谢任何帮助。（我使用VB.Net编写代码，使用Access＆＃39; 13作为数据库（可能是问题的一部分;我已经阅读了它，并且对语法非常挑剔）并使用VS 2013。）

@tim：根据要求，这里是完整的子。

Private Sub btnSearch_Click(sender As Object, e As EventArgs) Handles btnSearch.Click
    If cbSearchType.Text = "Guest Surname" Then

        Dim searchSQL As String = "SELECT bookings.bookingStartDate, bookings.bookingEndDate, guests.guestFirstName, guests.guestSurname, locations.locationName FROM bookings JOIN guests ON guests.guestID = bookings.guestID JOIN locations ON locations.locationID = bookings.locationID WHERE guests.guestSurname = @guestSurname"

        Dim searchCommand = New OleDbCommand(searchSQL, globalVariables.objConnection)
        Dim searchAdapter As New OleDbDataAdapter(searchSQL, globalVariables.objConnection)
        Dim searchDataTable As New DataTable

        searchCommand.Parameters.AddWithValue("guestSurname", tbSearchTextBox.Text)
        searchAdapter.SelectCommand = searchCommand
        searchAdapter.Fill(searchDataTable)

        globalVariables.objConnection.Open()
        searchAdapter.Fill(searchDataTable)
        gvSearchResults.DataSource = searchDataTable
        globalVariables.objConnection.Close()

    ElseIf cbSearchType.Text = "Location" Then

    ElseIf cbSearchType.Text = "Booking Start Date" Then

    ElseIf cbSearchType.Text = "Booking End Date" Then

    End If
End Sub

结束班

Answer 1

在Access中，您需要指定INNER JOIN。当有多个连接时，您还需要括号。我会把它写成：

SELECT b.bookingStartDate, b.bookingEndDate, g.guestFirstName, g.guestSurname, l.locationName
FROM (bookings as b INNER JOIN
      guests as g
      ON g.guestID = b.guestID) INNER JOIN
     locations as l
     ON l.locationID = b.locationID
WHERE g.guestSurname = @guestSurname;

SQL - FROM子句中的语法错误（JOIN）

1 个答案: