Get Last Modified date for PowerBI report from SQL
I am trying to get the last modified date from the database for reports in PowerBI to be used for request management as well as management level reports. I attempted to use the last modified date from here: http://www.techguy.at/system-center-service-managersql-query-to-get-a-full-list-of-your-incidents/, however, it was not giving me the latest time a comment was added to the request. I think searched through the relationships in the ServiceManager Database and come up with the SQL below. While it gives me the correct date in most cases, there still seems to be some NULL entries. Can someone point out what I am missing?
If needed, I can upload again after I have added comments to the SQL.
City of Richmond