How to access an external MySQL database in a view if SQLite support is not installed?
The Forena module is shipped with 3 types of "sample" reports:


Reports about your own Drupal database (the drupal/* 'data blocks' in your screenprint), typically in MySQL database format.
Forena tutorials, which are actually also delivered in the format of "Reports" which refer to datablocks in XML format (the forena_help/* 'data blocks' in your screenprint).
Reports about some Sample database which is also delivered with Forena, in the format of an SQLite database (none of these Sample/* 'data blocks' are shown in your screenprint, as they are normally shown when PDO driver support for SQLite is available).


So the error shown in your screenprint is to inform you about something like "sorry, there is no SQLite support available here, so I can't handle the Sample database (which is in SQLite format)".

If however you have MySQL support available on the server where your MySQL data resides (eg: if it's on the same server as where Drupal resides, but just another MySQL database), then you should be able to use Forena for creating reports about that MySQL database. To access that MySQL database, you need to define (within Forena admin) a Data Connection to that MySQL database and 1 or more data blocks (SQL queries). And from then on you should be able to build your custom reports about that MySQL database, e.g. using the WYSIWYG report writer that comes with Forena.

Note: if you're interested in trying out Forena, use SimplyTest.Me to do so. If you do, and after you login to such site, you'll also get the same PDO driver support for sqlite not installed error message, after you visit the "/reports" link for the first time (or use the "My Reports" menu option in the Navigation menu). That error is shown because support for SQLite is not enabled on SimplyTest.Me. You get a similar error message if you visit the reports/sample.toc link (because the sample reports and graphs are using an SQLite database). However, reports such as these run just fine (they don't require SQLite):


/reports/help.toc.
/reports/drupaladmin.enabled_contributions (by the way: shows all enabled modules in such simplytest.me setup ...).