ACC: How to Create a Top Values Per Group Report (132056)

SUMMARY

This article demonstrates how you can create a report that ranks a specific number of records for each group in order according to a top value, for example, the top five selling products per category.

NOTE: This article explains a technique demonstrated in the sample files, RptSampl.exe (for Microsoft Access for Windows 95 version 7.0) and RptSmp97.exe (for Microsoft Access 97). For information about how to obtain these sample files, please see the following articles in the Microsoft Knowledge Base:

145777 ACC95: Microsoft Access Sample Reports Available in Download Center

175072 ACC97: Microsoft Access 97 Sample Reports Available in Download Center

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Microsoft Access has a TopValues property that you can use in a query to return a specific number (N) or a specified percentage (N%) of records. Using a main/sub report with a query that has a value set for its TopValues property, you can create a report listing the top N records for each group.

To create a top values per group report, follow these steps:

Open the sample database Northwind.mdb (or NWIND.MDB in version 2.0).
Create a new, blank report based on the Categories table, and open it in Design view.
If the field list is not displayed, on the View menu, click Field List, and drag the CategoryId and CategoryName fields from the field list to the report's detail section. Close and save report as Top_N_Per_Group.

NOTE: In version 2.0, there is a space in the Category ID and Category Name fields.

Create a new query based on the Order Details and Products tables as follows:

       Query: Top_N_Products
       ----------------------------------------------------------

          Type: Select Query
          Join: Order Details.[ProductID] <-> Products.[ProductID]
          TopValues: 5

          NOTE: In version 2.0, type a space in the Product ID field.

          Field: CategoryID
          Table: Products
          Total: Group By
          Criteria: [Reports]![Top_N_Per_Group]![CategoryID]

          NOTE: In version 2.0, type a space in the Category ID field.

          Field: ProductName
          Table: Products
          Total: Group By

          NOTE: In version 2.0, there is a space in the Product Name field.

          Field: SaleAmount: Sum([Order Details].[UnitPrice]*[Quantity])
          Total: Expression
          Sort: Descending

          NOTE: In version 2.0, type a space in the Unit Price field.

          NOTE: Referencing the CategoryID from the Top_N_Per_Group report
          as criteria ensures that this query filters records by CategoryID
          before it applies the TopValues property to the recordset.

Close and save the query as Top_N_Products.
Create a new, blank report based on the Top_N_Products query.
If it is not displayed, on the View menu, click Field List and drag the ProductName and SaleAmount fields from the field list to the report's detail section. Close and save the report as Top_N_Sub.

NOTE: In version 2.0, there is a space in the Product Name and Sale Amount fields.
Open the Top_N_Per_Group report in Design view.
With the report open in Design view, press the F11 key to switch to the Database window.
From the Database window, drag the Top_N_Sub report to the detail section of the Top_N_Per_Group report.
Click the Top_N_Sub report and open its property sheet.
Delete CategoryID from the LinkChild and LinkMaster properties.
Preview the report. Note that the Top_N_Sub subreport displays the top five selling products for each category.

ACC: How to Create a Top Values Per Group Report (132056)

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