Assistance with query

I know I am probably making this much more difficult than it needs to be but I have not been able to come up with a solution.  I have the following query which returns the data I need. Now, however, I have been asked to provide another column which is the description of the parent account for each account in the query.  I have another view XX_Account_HIer_V which has account number, description and parent account number for all accounts including the parent accounts.  So what I need to figure out the syntax for is how to say --when the bl.account_number=Hier.account number,