KB20306: How to create dynamic date based on 'Last Month' in MicroStrategy SQL Generation Engine 9.4.x-10.x using an Oracle database

The Dynamic Dates in Strategy SQL Generation Engine 9.4.x-10.x use the Day attribute to qualify on a particular date. Thus, if a Dynamic Date is created based on today's date, in order to get 'Last Month' a specific number of days can be subtracted from the date. But since the length of the month ranges between 28-31 days it is almost impossible to get the correct output based on the Day attribute.
 
If users want to have the output based on a different Attribute other that Date (e.g., month), they must follow the steps below:
 

1. Create a new filter based on Attribute Qualification
2. Select the desired attribute (in this case, the Month attribute).
3. Select Qualify On as ID
4. Select Operator as Exactly
5. Select Custom and use the following expression:
   ApplySimple ("(to_number (to_char (sysdate, 'MM')) -1)", 0)
   

Please find below the screenshot of the filter editor:

 
Also, find below the SQL for this report:
 
Select a11.MONTH_ID MONTH_ID,
a11.MONTH_DESC MONTH_DESC
From LU_MONTH a11
Where a11.MONTH_ID = (to_number (to_char (sysdate, 'MM')) -1)
NOTE:
This expression was designed for Oracle but similar SQL can be generated for other databases.