BITMAP_BUCKET_NUMBER
Purpose
Use BITMAP_BUCKET_NUMBER to construct a one-to-one mapping between a number and a bit position in a bitmap.
                  
The argument expr is of type NUMBER. It represents the absolute bit position in the bitmap.
                  
BITMAP_BUCKET_NUMBER returns a NUMBER. It represents the relative bit position. 
                  
If expr is NULL, the function returns NULL.
                  
If expr is not an integer, you will see the following error message:
                  
Invalid value has been passed to a BITMAP COUNT DISTINCT related operator.