We have a custom reporting module, which we would recommend you use first.  The main advantages are that it includes all the complex table joins, and can be updated in a single place when they are modified.  It is also very easy to use, so a report could be created by almost anyone within a few minutes – senior management, or an assistant on their first day.  There is of course more detail available in a direct database query, so please provide some examples of your most complex reports, and we shall check if they could be created with our data analytics tool.