Filtering data after row retrieval
It is recommended to filter at the data source when possible. There are cases, however, when you cannot. BIRT provides options for filtering data that complement, and in some cases, replace filtering provided by data sources. For example, if a report uses a flat file data source, you can filter data in BIRT only.
In addition, if using SQL to modify an existing database query is problematic, you can specify the filter conditions using JavaScript expressions instead of SQL. BIRT Report Designer provides a graphical tool to help you build these filter conditions.