VB.Net SQL Query不能在VB中工作，但在Access中工作

Question

我试图找出为什么这个查询不返回结果。 相同的查询在Access中工作正常，但在VB.Net中没有。 任何帮助，将不胜感激。 尝试填充数据集时代码失败。 谢谢。

Function Populate_Month()

    Dim dbConnection As New OleDbConnection
    Dim dbConnectionStr As String
    Dim dbProvider As String
    Dim dbSource As String

    dbProvider = "Microsoft.Jet.OLEDB.4.0;"
    dbSource = "C:\Users\Scraps\Documents\Gossamer.mdb"

    dbConnectionStr = "Provider=" & dbProvider & "Data Source=" & dbSource
    dbConnection = New OleDbConnection(dbConnectionStr)
    dbConnection.Open()

    Dim dbAdapter As OleDbDataAdapter
    Dim dbDataSet = New DataSet
    Dim dbQueryStr As String
    Dim CurrentRow As Integer

    dbQueryStr = "SELECT * FROM Forecast_TDL" & _
         "WHERE Forecast_TDL.EIAC & Forecast_TDL.LCN & Forecast_TDL.Servicing & Forecast_TDL.Interval & Forecast_TDL.Interval_Type" & _
         "NOT IN (SELECT EIAC & LCN & Servicing & Interval & Interval_Type FROM Grouped_Servicings);"

    dbAdapter = New OleDbDataAdapter(dbQueryStr, dbConnection)

    dbAdapter.Fill(dbDataSet, "forecast")
    CurrentRow = 0
    MsgBox(dbDataSet.Tables("forecast").Rows(CurrentRow)("Interval"))

    dbConnection.Close()
    Return Nothing

End Function

Answer 1

从我的观点来看，你需要在“Where”和“Not in”之类的子句之前使用空格。 并在查询结束时删除分号。

Answer 2

在MS Access中也没有办法。 你必须做类似的事情：

 
 
 
 
  
  
  SELECT * FROM Forecast_TDL WHERE Forecast_TDL.EIAC NOT IN(SELECT EIAC FROM Grouped_Servicings) AND Forecast_TDL.LCN NOT IN(SELECT LCN FROM Grouped_Servicings) AND Forecast_TDL.Servicing NOT IN(SELECT Servicing FROM Grouped_Servicings) And Forecast_TDL.Interval NOT IN(SELECT Interval FROM Grouped_Servicings) And Forecast_TDL.Interval_Type NOT IN (SELECT Interval_Type FROM Grouped_Servicings)
 
 
  

在更好地理解问题之后，您可以避免使用JOIN比较连接字符串并找到不存在行的位置。

SELECT * FROM Forecast_TDL
LEFT OUTER JOIN Grouped_Servicings
ON Forecast_TDL.EIAC = Grouped_Servicings.EIAC AND
 Forecast_TDL.LCN = Grouped_Servicings.LCN AND
 Forecast_TDL.Servicing = Grouped_Servicings.Servicing AND
 Forecast_TDL.Interval = Grouped_Servicings.Interval AND
 Forecast_TDL.Interval_Type = Grouped_Servicings.Interval_Type
WHERE Grouped_Servicings.EIAC IS NULL OR
      Grouped_Servicing.LCN IS NULL OR
      Grouped_Servicing.Servicing IS NULL OR
      Grouped_Servicing.Interval IS NULL OR
      Grouped_Servicing.Interval_Type IS NULL