How to create a top values per group report in Access 2002 (296449)

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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. By 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.

For an example of how to create a top values per group report, follow these steps:

1. Open the sample database Northwind.mdb.
2. Create a new, blank report based on the Categories table, and then open it in Design view.
3. If the field list is not displayed, on the View menu, click Field List, and then drag the CategoryID and CategoryName fields from the field list to the detail section of the report. Save the report as Top_N_Per_Group, and then close it.
4. Create a new query that is 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
      
      Field: CategoryID
      Table: Products
      Total: Group By
      Criteria: [Reports]![Top_N_Per_Group]![CategoryID]
   
      Field: ProductName
      Table: Products
      Total: Group By
   
      Field: SaleAmount: Sum([Order Details].[UnitPrice]*[Quantity])
      Total: Expression
      Sort: Descending
   						

   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.
5. Save the query as Top_N_Products, and then close it.
6. Create a new, blank report that is based on the Top_N_Products query.
7. If the field list is not displayed, on the View menu, click Field List, and then drag the ProductName and SaleAmount fields from the field list to the detail section of the report. Save the report as Top_N_Sub, and then close it.
8. Open the Top_N_Per_Group report in Design view.
9. On the Window menu, click Tile Horizontally.
10. Drag the Top_N_Sub report from the Database window to the detail section of the Top_N_Per_Group report.
11. On the Window menu, click Cascade.
12. Click the Top_N_Sub report, and then open its property sheet.
13. Delete CategoryID from the LinkChild and LinkMaster properties.
14. Preview the report. Note that the Top_N_Sub subreport displays the top five selling products for each category.