Sorry you never got a response on this. Are you still looking for a solution?
Are you able to create a Tableau Data Extract from the data? Would doing so allow you to aggregate to the YEAR level? I'm not familiar with HANA, so I'm afraid I cannot offer any other suggestions.
I need to update that post that I was able to work with my IT department and they added the correct date field that works in my report.
No problem, just make sure to mark your question as "Assumed Answered" or otherwise answered in some way, so others know you've found a solution. Thanks!