If you don't mind some SQL work, [Forena][1] 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][1] 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:

 - [Community documentation][2].
 - Documentation that comes with Forena, which you can access right after install and enable of the module. Checkout the [demo site][3] 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:

 1. 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][4]: the data shown there are data contained in the sampledb, which is in SQLite format.
 2. Forena comes with a full suite of [Supported database connections][5] ... 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 aware: I'm a co-maintainer of Forena.

  [1]: https://www.drupal.org/project/forena
  [2]: https://www.drupal.org/node/2041363
  [3]: http://www.forenasolutions.org
  [4]: http://forenasolutions.org/reports/samples
  [5]: https://www.drupal.org/node/2041363#dbconnections