訪問數據庫 - 「單一」的錯誤

Question

我從行SingleRoom = dr("Single").ToString中收到錯誤「單一」。我沒有編程很久。我希望能夠在數據庫中搜索最新日期（Last Modified），然後使用同一行中其他字段的數據作爲標籤顯示。

Dim PriceFound As String = False 
    MyConn = New OleDbConnection 
    MyConn.ConnectionString = connString 
    MyConn.Open() 


    str1 = ("SELECT `Last Modified` FROM [Prices] ORDER BY `Last Modified` DESC") 


    Dim cmd1 As OleDbCommand = New OleDbCommand(str1, MyConn) 

    dr = cmd1.ExecuteReader 

    While dr.Read() 

     PriceFound = True 
     DateDisplay = dr("Last Modified").ToString 
     SingleRoom = dr("Single").ToString 
     DoubleRoom = dr("Double").ToString 
     FamilyRoom = dr("Family").ToString 
     AdultPrice = dr("Adult").ToString 
     ChildPrice = dr("Child").ToString 

     If PriceFound = True Then 
      LblPriceAdult.Text = AdultPrice 
      LblPriceChild.Text = ChildPrice 
      LblPriceDoubleRoom.Text = DoubleRoom 
      LblPriceFamilyRoom.Text = FamilyRoom 
      LblPriceSingleRoom.Text = SingleRoom 
     End If 
    End While 
    MyConn.Close() 

Answer 1

您的查詢應該有可能是：

"SELECT * FROM [Prices] ORDER BY `Last Modified` DESC" 

...所以它會檢索SELECT子句中的其他列/字段。當前查詢只檢索Last Modified列。

=====

另外，如果你想只能選擇特定的列，你可以在查詢做到這一點：

注意，列的順序是不重要 - 我只是在這個例子中與你的列表相匹配。

"SELECT `Last Modified`, Single, Double, Family, Adult, Child FROM [Prices] ORDER BY `Last Modified` DESC"