HOWTO: Populate DBGrid from Crosstab Parameter Query

• Microsoft Visual Basic Professional and Enterprise Editions for Windows, version 5.0
• Microsoft Visual Basic Professional and Enterprise Editions, 16-bit and 32-bit, for Windows, version 4.0

SUMMARY

This article demonstrates how to create a Parameter Crosstab Query using the sample Nwind.mdb Access database file. It also explains how to create a recordset in Visual Basic by running the query, passing the necessary parameters to it, and then populating a Visual Basic DBGrid with the resultant recordset.

MORE INFORMATION

The following example uses the sample Nwind database that ships with Visual Basic. Note that it is recommended to explicitly declare the parameters when creating and running Crosstab Parameter Queries. See the REFERENCES section of this article for more information.

1. Create a new Project in Visual Basic.

2. From the menu, select Project - References and make a reference to Microsoft DAO 3.5 Object Library. In Visual Basic 4.0, under Tools references make, a reference to DAO 3.0 object library.

3. From the menu, select Project - Components and select a Data Bound Grid control. In Visual Basic 4.0, this is under Tools - Custom Controls.

4. Add a CommandButton, a Data Control and a DBGrid Control to the new Form.

5. Accept the default Names for the Command Button, DBGrid, and Data Control.

6. Enter the sample code below into the General Declarations of the Form.

7. In the properties Window, set the DataSource property of the DBGrid to Data1 to bind the DBGrid to the Data control.

8. Run the application and click the CommandButton.

   Sample code:

         Private Sub Command1_Click()
           Dim Sql As String
           Dim DatabaseFile As String
           Dim MyDB As Database
           Dim RS As Recordset
           Dim QD As QueryDef
      
         On Error GoTo errorHand
      
         'This is the Path & Database filename.
         'Change to match your path and filename.
         DatabaseFile = "C:\VB5\Nwind.mdb"
      
         'Create the querydef SQL string
         Sql = "Parameters [Enter first date] DateTime, " _
            & "[Enter second date] DateTime;"
         Sql = Sql & " TRANSFORM Sum(CCur([Order Details].[UnitPrice]" _
            & " *[Quantity]*(1-[Discount])/100)*100) AS ProductAmount"
         Sql = Sql & " SELECT Products.ProductName, Orders.CustomerID," _
            & " Year([OrderDate]) AS OrderYear"
         Sql = Sql & " FROM Products INNER JOIN (Orders INNER JOIN" _
            & " [Order Details] ON Orders.OrderID ="
         Sql = Sql & " [Order Details].OrderID) ON" _
            & " Products.ProductID = [Order Details].ProductID"
         Sql = Sql & " WHERE (((Orders.OrderDate) Between" _
            & " [Enter first date] And [Enter second date]))"
         Sql = Sql & " GROUP BY Products.ProductName, Orders.CustomerID," _
            & " Year([OrderDate])"
         Sql = Sql & " PIVOT 'Qtr ' & DatePart('q',[OrderDate],1,0) In" _
            & " ('Qtr 1','Qtr 2','Qtr 3','Qtr 4');"
   
         'This code creates the parameter query
      
         Set MyDB = DBEngine(0).OpenDatabase(DatabaseFile)
         Set QD = MyDB.CreateQueryDef("CrossTabParamQuery")
         With QD
             .Sql = Sql
             .Parameters("[Enter first date]") = #1/1/95#
             .Parameters("[Enter second date]") = #1/1/96#
         End With
         Set Rs = QD.OpenRecordset(dbOpenDynaset)
         Set Data1.Recordset = Rs
         Exit Sub
      
         errorHand:
         If Err.Number = 3012 Then   ' The querydef exists
             MyDB.QueryDefs.Delete "CrossTabParamQuery"
             Resume
         Else
             MsgBox Err.Number & "  " & Err.Description
         End If
         End Sub
      
         Private Sub Form_Unload(Cancel As Integer)
            RS.Close
            QD.Close
            MyDB.Close
         End Sub
   
   

REFERENCES

Visual Basic Help topic "PARAMETERS Declaration"

For more information, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q91710
   TITLE     : Can't Bind Name '[XXX]'" Error with Crosstab Query

Keywords          : VB4ALL VB4WIN vb5all kbhowto
Component         : jet
Version           : WINDOWS:4.0,5.0
Platform          : WINDOWS
Issue type        : kbhowto