Отдел по ошибке Zero в запросе кросс-таблицы

Question

Я уже некоторое время успешно запускаю этот код, используя сокращенный набор данных, содержащий приблизительно 15 акций с историческими ценами акций (например: http://ichart.yahoo.com/table.csv?s=goog). Я просто увеличил объем данных примерно до 6 000 акций (920 570 записей в моем DataTable), и теперь у меня возникают некоторые проблемы.

Вот код:

Public Sub Update_Quarterly_Growth_Rates() 
    ToolStripStatusLabel2.Text = "Updating Quarterly Growth Rates" 
    con.Open() 
    Try 
     Dim cmd As OleDbCommand = New OleDbCommand("CREATE PROC Stock_Price_with_qtr AS SELECT Historical_Stock_Prices.*, Year([Date]) AS [Year], Switch(Month([Date])<4,1,Month([Date])<7,2,Month([Date])<10,3,True,4) AS Qtr FROM Historical_Stock_Prices", con) 
     cmd.ExecuteNonQuery() 
    Catch ex As Exception 
    Finally 
     Dim cmda As OleDbCommand = New OleDbCommand("DROP PROCEDURE Stock_Price_with_qtr", con) 
     cmda.ExecuteNonQuery() 
     Dim cmdb As OleDbCommand = New OleDbCommand("CREATE PROC Stock_Price_with_qtr AS SELECT Historical_Stock_Prices.*, Year([Date]) AS [Year], Switch(Month([Date])<4,1,Month([Date])<7,2,Month([Date])<10,3,True,4) AS Qtr FROM Historical_Stock_Prices", con) 
     cmdb.ExecuteNonQuery() 
    End Try 

    Try 
     Dim cmd1 As OleDbCommand = New OleDbCommand("CREATE PROC Qtr_Dates AS SELECT Stock_Price_with_qtr.Ticker, Stock_Price_with_qtr.[Year], Stock_Price_with_qtr.Qtr, Min(Stock_Price_with_qtr.[Date]) AS Qtr_Start, Max(Stock_Price_with_qtr.[Date]) AS Qtr_End FROM Stock_Price_with_qtr GROUP BY Stock_Price_with_qtr.Ticker, Stock_Price_with_qtr.[Year], Stock_Price_with_qtr.Qtr", con) 
     cmd1.ExecuteNonQuery() 
    Catch ex As Exception 
    Finally 
     Dim cmd1a As OleDbCommand = New OleDbCommand("DROP PROCEDURE Qtr_Dates", con) 
     cmd1a.ExecuteNonQuery() 
     Dim cmd1b As OleDbCommand = New OleDbCommand("CREATE PROC Qtr_Dates AS SELECT Stock_Price_with_qtr.Ticker, Stock_Price_with_qtr.[Year], Stock_Price_with_qtr.Qtr, Min(Stock_Price_with_qtr.[Date]) AS Qtr_Start, Max(Stock_Price_with_qtr.[Date]) AS Qtr_End FROM Stock_Price_with_qtr GROUP BY Stock_Price_with_qtr.Ticker, Stock_Price_with_qtr.[Year], Stock_Price_with_qtr.Qtr", con) 
     cmd1b.ExecuteNonQuery() 
    End Try 

    Try 
     Dim cmd2 As OleDbCommand = New OleDbCommand("CREATE PROC Quarterly_Growth_Rates AS SELECT Qtr_Dates.Ticker, Qtr_Dates.[Year], Qtr_Dates.Qtr, (([Close_Prices]![Close]/[Open_Prices]![Open])-1)*100 AS Growth_Rate FROM (Historical_Stock_Prices AS Open_Prices INNER JOIN Qtr_Dates ON (Open_Prices.Ticker = Qtr_Dates.Ticker) AND (Open_Prices.[Date] = Qtr_Dates.Qtr_Start)) INNER JOIN Historical_Stock_Prices AS Close_Prices ON (Qtr_Dates.Ticker = Close_Prices.Ticker) AND (Qtr_Dates.Qtr_End = Close_Prices.[Date])", con) 
     cmd2.ExecuteNonQuery() 
    Catch ex As Exception 
    Finally 
     Dim cmd2a As OleDbCommand = New OleDbCommand("DROP PROCEDURE Quarterly_Growth_Rates", con) 
     cmd2a.ExecuteNonQuery() 
     Dim cmd2b As OleDbCommand = New OleDbCommand("CREATE PROC Quarterly_Growth_Rates AS SELECT Qtr_Dates.Ticker, Qtr_Dates.[Year], Qtr_Dates.Qtr, (([Close_Prices]![Close]/[Open_Prices]![Open])-1)*100 AS Growth_Rate FROM (Historical_Stock_Prices AS Open_Prices INNER JOIN Qtr_Dates ON (Open_Prices.Ticker = Qtr_Dates.Ticker) AND (Open_Prices.[Date] = Qtr_Dates.Qtr_Start)) INNER JOIN Historical_Stock_Prices AS Close_Prices ON (Qtr_Dates.Ticker = Close_Prices.Ticker) AND (Qtr_Dates.Qtr_End = Close_Prices.[Date])", con) 
     cmd2b.ExecuteNonQuery() 
    End Try 
    Close() 
    ToolStripStatusLabel2.Text = "" 
End Sub 

Private Sub Load_Quarterly_Growth_Rates() 
    con.Open() 
    Dim cmd3 As OleDbCommand = New OleDbCommand("TRANSFORM First(y.Growth_Rate) AS FirstOfGrowth Select y.Ticker FROM Quarterly_Growth_Rates AS y GROUP BY y.Ticker ORDER BY y.Year & '-' & y.Qtr DESC PIVOT y.Year & '-' & y.Qtr", con) 
    Dim reader As OleDbDataReader = cmd3.ExecuteReader() 
    Dim da As New DataTable 
    da.Load(reader) 
    DataGridView_Quarterly_Growth_Rates.DataSource = da 
    reader.Close() 
    con.Close() 
End Sub 

При попытке отобразить запрос, загружая его в DataGridView, я получаю ошибку Division by zero. Я не совсем уверен, куда идти отсюда. Наверное, я хотел бы игнорировать любые результаты, на которые влияет деление на ноль и просто возврат пустого.

Answer 1

В обоих вычислениях роста, использовать что-то вроде

IIf([Open_Prices]![Open] <> 0, 
    (([Close_Prices]![Close]/[Open_Prices]![Open])-1)*100, 
    null 
    ) 

вместо

(([Close_Prices]![Close]/[Open_Prices]![Open])-1)*100 

Это проверка на 0 и избегает выполнения деления, если знаменатель будет 0.