将Access查询转换为VB.net SQL语句

Question

我的Access数据库中有一个名为Historical_Stock_Prices的表，里面装满了各种公司的历史股票价格。我需要运行一个查询，将原始数据(股票价格)转换为季度增长率，并在DataGridView中显示季度增长率。

我已经在Access数据库的SQL视图中编写了以下查询，并在Access中工作。

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);

我需要能够在我的程序中调用它，并在DataGridView中显示结果。我尝试从Access复制SQL语句，并在代码中将它作为SQL语句使用，但它不起作用。我没有发现任何错误，DataGridView只是空白。到目前为止，我的代码如下：

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

我真的被困住了，需要帮助！谢谢!

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Answer 1

您希望VB.Net代码重新创建在Access中工作的相同的SELECT语句。但是，看看Vim的语法突出显示，我认为您可能实际上正在创建其他的东西。(这可能就像创建一个字符串，作为其他两个字符串的区别："string 1" - "string 2")。

但是，不管我是否猜对了，使用字符串变量来保存您的SELECT语句。然后将该字符串打印到控制台或将其写入文本文件，以便您可以检查给db引擎的实际语句。

或者将Access中的工作查询保存为一个命名查询对象，并使用您的VB.Net代码中的查询名称--这将绝对保证使用相同的SQL，后者在Access中被确认可以工作。