小编Dom*_*ius的帖子

有没有人有一个如何连接3个表的例子,我有以下语句,但我得到一个缺少a(语法错误"操作员错误")

da = New OleDbDataAdapter("SELECT [S].[Scheduled Vege], [V].[Description], 
        [DS].[Task], [DS].[Task Date], [DS].[Completed] FROM [Scheduled] AS S 
        INNER JOIN [Date Schedules] AS DS ON [S].[SchedID] = [DS].[SchedID] 
        INNER JOIN [Vegetables Descriptions] AS V ON [V].[Task] = [DS].[Task] 
        WHERE [DS].[TaskNumber] >= " & aFromDate & " AND [DS].[TaskNumber] <= " & aToDate & " 
        AND [DS].[Completed] = '" & aCompleted & "' ", conn)

谢谢

    Dim conn As OleDbConnection
    Dim cmd As OleDbCommand

    Public Sub openDB()
        conn = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Application.StartupPath & "\VFMS_DB.mdb;" & "Jet OLEDB:System Database=Security.mdw;User ID=Adster;Password=300624;")
        conn.Open()
    End Sub

    Public Function UpdateUser() As Integer
        Dim retCode As New Integer

        Try
            openDB()
            cmd = conn.CreateCommand()

下面的更新命令一直给我这个错误:"从字符串转换"'WHERE [Username] ='"到'Double'类型无效." 而且我不知道为什么.aUserName字段是一个String字段,我检查以确保它已填充.

            cmd.CommandText = "UPDATE Users SET [First Name] = '" & aName & "', [Last Name] = '" & aSurname & "', [Contact Number] = '" & aContactNum & "', [Password] = '" & …

我试图做一个内连接选择语句,我从表中选择两个字段,而不是第二个表中与第一个表具有相同id的字段的所有记录.

代码如下:

    Dim conn As OleDbConnection
    Dim cmd As OleDbCommand

    Public Sub openDB()
        rsConn = New ADODB.Connection
        rsConn.Open("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Application.StartupPath & "\VFMS_DB.mdb;" & "Jet OLEDB:System Database=Security.mdw", "ADMIN", "1234")
    End Sub

    Public Function GetProdDetails(ByVal vegeID As Integer, ByRef dsTask As DataSet) As Integer

        Dim retCode As New Integer

        Dim da As OleDbDataAdapter

        Try
            Dim i As Integer = 0

            openDB2()

            da = New OleDbDataAdapter("SELECT [Vegetables Descriptions.Task], [Vegetables Descriptions.Description], [TasksOcc.When] FROM [Vegetables Descriptions] INNER JOIN [TasksOcc] ON [Vegetables Descriptions.DescID] = [TasksOcc.DescID] …