將訪問查詢轉換為VB.net SQL語句

Question

我的Access數據庫中有一個名為Historical_Stock_Prices的表，該表充滿了各個公司的歷史股價。 我需要運行一個查詢，將原始數據（股票價格）轉換為季度增長率，並在DataGridView顯示季度增長率。

我已經在Access數據庫的SQL視圖中編寫了以下查詢，該查詢在Access中有效。

SELECT MinMaxYrQtrDates.YrQtr, MinMaxYrQtrDates.Ticker, MinMaxYrQtrDates.MaxDate, [Historical Prices].Close, MinMaxYrQtrDates.MinDate, [Historical Prices_1].Open, ([Historical Prices].[Close]/[Historical Prices_1].[Open]-1)*100 AS GrowthRate FROM [Historical Prices] AS [Historical Prices_1] INNER JOIN ([Historical Prices] INNER JOIN [SELECT Year([Date]) & "-" & DatePart("q",[Date]) AS YrQtr, [Historical Prices].Ticker, Max([Historical Prices].Date) AS MaxDate, Min([Historical Prices].Date) AS MinDate FROM [Historical Prices] GROUP BY Year([Date]) & "-" & DatePart("q",[Date]), [Historical Prices].Ticker]. AS MinMaxYrQtrDates ON ([Historical Prices].Date = MinMaxYrQtrDates.MaxDate) AND ([Historical Prices].Ticker = MinMaxYrQtrDates.Ticker)) ON ([Historical Prices_1].Ticker = MinMaxYrQtrDates.Ticker) AND ([Historical Prices_1].Date = MinMaxYrQtrDates.MinDate);

我需要能夠從程序中調用它並將結果顯示在DataGridView 。 我試圖從Access復制SQL語句並將其用作代碼中的SQL語句，但是它不起作用。 我沒有任何錯誤， DataGridView只是空白。 到目前為止，這是我的代碼：

Imports System.IO
Imports System.Data.OleDb

Public Class Historical_Growth_Rates_Annual

Public tblName As String = "Historical_Stock_Prices"

Private Sub Historical_Growth_Rates_Annual_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    If (File.Exists(Nordeen_Investing_3.databaseName)) Then
        Nordeen_Investing_3.con.Open()
        Dim restrictions(3) As String
        restrictions(2) = tblName
        Dim dbTbl As DataTable = Nordeen_Investing_3.con.GetSchema("Tables", restrictions)
        If dbTbl.Rows.Count = 0 Then
            MessageBox.Show("Historical Stock Prices tables does not exist in the database.  Please Update")
        Else
            Dim da As OleDbDataAdapter = New OleDbDataAdapter("SELECT MinMaxYrQtrDates.YrQtr, MinMaxYrQtrDates.Ticker, MinMaxYrQtrDates.MaxDate, [Historical_Stock_Prices].Close1, MinMaxYrQtrDates.MinDate, [Historical_Stock_Prices_1].Open1, ([Historical_Stock_Prices].[Close1]/[Historical_Stock_Prices_1].[Open1]-1)*100 AS GrowthRate FROM [Historical_Stock_Prices] AS [Historical_Stock_Prices_1] INNER JOIN ([Historical_Stock_Prices] INNER JOIN [SELECT Year([Date1]) & " - " & DatePart('q',[Date1]) AS YrQtr, [Historical_Stock_Prices].Ticker, Max([Historical_Stock_Prices].Date) AS MaxDate, Min([Historical_Stock_Prices].Date) AS MinDate FROM [Historical_Stock_Prices] GROUP BY Year([Date1]) & " - " & DatePart('q',[Date1]), [Historical_Stock_Prices].Ticker]. AS MinMaxYrQtrDates ON ([Historical_Stock_Prices].Date = MinMaxYrQtrDates.MaxDate) AND ([Historical_Stock_Prices].Ticker = MinMaxYrQtrDates.Ticker)) ON ([Historical_Stock_Prices_1].Ticker = MinMaxYrQtrDates.Ticker) AND ([Historical_Stock_Prices_1].Date = MinMaxYrQtrDates.MinDate);", Nordeen_Investing_3.con)
            'create a new dataset
            Dim ds As New DataSet()
            'fill the datset
            da.Fill(ds)
            'attach dataset to the datagrid
            DataGridView1.DataSource = ds.Tables(0)
            ds = Nothing
            da = Nothing
            Nordeen_Investing_3.con.Close()
        End If
    Else
        MessageBox.Show("Database does not exist.  Please update.")
    End If
End Sub
End Class

我真的很困，可以尋求幫助！ 謝謝！

Answer 1

您希望VB.Net代碼重新創建可在Access中使用的相同SELECT語句。 但是，看看Vim突出顯示的語法，我認為您可能實際上正在創建其他東西。 （這可能就像創建一個字符串來區別其他兩個字符串： "string 1" - "string 2" ）。

但是，無論我是否猜對了，都使用字符串變量來保存您的SELECT語句。 然后將該字符串打印到控制台或將其寫入文本文件，以便您可以檢查要提供給db引擎的實際語句。

或將工作查詢保存為Access中的命名查詢對象，並使用您的VB.Net代碼中的查詢名稱---絕對可以保證使用與確認在Access中工作相同的SQL。