If you don't mind some SQL work, Forena might be a module for you. Without all that neat and nice features like report skins (a kind of templating) - which might be unneeded in your case - it's much lighter, cleaner and faster.
Forena can be used to query (not update) any MySQL database table (that includes any Drupal table also).
For more details about Forena, 2 types of documentation are available these days:
Documentation that comes with Forena, which you can access right after install and enable of the module. Checkout the demo site for an online example of the current:
Forena documentation - use the link 'Reporting documentation' or visit relative link /reports/help.
Forena samples - use the link 'Reporting samples' or visit relative link /reports/samples (these samples are fully functional, so make sure to experiment a bit with it, such as the drill downs available on the SVG Graph sample).
The newest 7.x-4.x version also includes an amazing (I think) UI for either creating your reports (the WYSIWYG report editor) and/or for creating your SQL queries (the Query Builder).
Here are some variations of the MySQL database part in my answer:
- Using a SQLite instead of MySQL database: the Forena samples actually get shipped including a (Tiny) SQLite database. Go check it out in the demo site: the data shown there are data contained in the sampledb, which is in SQLite format.
- Forena comes with a full suite of Supported database connections ... such as MS SQL, Oracle, Postgress or any PDO compliant variation.
Enough reasons for considering giving Forena a try? While doing so, use it's issue queue for any type of support/docu requests you may have.
Be awareDisclaimer: I'mPierre.Vriens (answer editor) is a co-maintainer of Forena.