I need to know what tables and fields are used for the CiviCRM reports, I've been dealing for several weeks trying to see why an updated site from CiviCRM 4.2 to 4.7.16 on Joomla is not showing any reports, I need to see if several tables changed or fields and where to look into why they are not showing up as they don't show any errors, they only show no result at all. Thank you.
4.2->4.7 is a huge upgrade. Swathes of tables - including Activities and Settings - have changed. If you have any custom reports or extensions these definitely will need to be upgraded without a doubt.
This could be caused by a number of things.
Is this all reports, or just some? What are the names of the failing reports?
Please could you provide a screenshot?
Have you looked in the CiviCRM error logs and the Joomla! logs?
Agree with JohnFF, if you have customized reports and are moving from 4.2 to 4.7 you will almost certainly need to upgrade each and everyone of those reports.