A filter applied in the Query section instructs the database server to filter unwanted information from your request. Only the filtered data is returned to your desktop.
If your query is potentially large, and you are more or less certain of both the information you need and how to define the correct filters, it is best to apply filters in the Query section. By using the database server to filter the data, you return only the data you need across the network and onto your computer.
Another advantage of applying filters in the Query section is that you can apply a filter to any topic item in the data model, even if the item is not on the Request line. For example, if you request State, Year and Units Sold, you can filter any of these items. But you can also place a filter on Operating System (OS) if it is displayed in one of the topics in the work area. If you filter OS to the UNIX only, the server retrieves only sales information related to the UNIX operating system. You need not place OS on the Request line.