Filtering Datasets

I have the following report



1. A mulitvalued parameter State with WA, SA, QLD, TAS etc

2. A single value parameter of Top n - 10, 20, 40



The user will select the state and the top number to get the top n sellers off that state or a combination off states.



I have a dataset with the following cutdown version off SQL





Declare @TopNo Int

Set @TopNo = @Param_TopNo

Set Rowcount @TopNo



SELECT CreateDate,SaleDate,sales.Consultant, State, Sum(Value) As Winbacks

FROM dbo.tbl_kpi_sales

GROUP BY CreateDate, Consultant, State, SaleDate, Winbacks

ORDER BY Winbacks Desc;



Set RowCount 0


When I execute it and select 'Select all' from the mulitvalued state parameter with a Top N value off 100 the query returns all the top 100, which is correct, however when i select just a single state ie WA it only returns me the records which were in the TOP 100 off all states when it should be filtering it by only the state I choose and returning the 100 records...For some reason it when a single state is selected or a combination off states the dataset is already narrowed down and doesnt reexecute the query for just that state...Can someone suggest how to overcome this, maybe a table filter ?