KB16233: How to use a custom expression to filter on previous months dynamically in MicroStrategy Developer 9.x and newer

Users may need to filter the data to the previous months dynamically based on the current month similar to dynamic date filtering.
To create a filter that qualifies dynamically on months prior to the current month, users need to create a custom expression in an advanced qualification through Strategy Developer
 
The following example is created with Strategy Tutorial project:

• Create a new filter in Strategy Developer
• Choose the 'Add an advanced qualification' option and click on the 'OK' button.
• By default, 'Custom Expression' is the option selected for a new Advanced Qualification.
• Enter the following expression: ApplyComparison("{Current Month function} > #0", Month@ID )
  

•  
  ApplyComparison( "To_number(To_char(SYSDATE,'YYYYMM')) > #0", Month@ID)
  
• {Current Month} is the warehouse database vendor specific syntax to determine the current month in the appropriate format. The illustration above uses Oracle syntax.
   
  
• Validate the expression by clicking on 'Validate'
• Click the 'OK' button to complete the qualification.
• Click the 'Save and Close' button in the Filter Editor toolbar.