Just place some SQL on in the box and save it as a report. You can save multiple reports and they will be listed on the Admin Menu so you can quickly run them again anytime with just one click. You can place your reports on the User’s Dashboard based on Roles. You can also put a report on a Page or Post using a shortcode like [SQLREPORT name=”My Report” style=”padding: 6px;” /]
There is also an shortcode for the wpdb::get_var function that you can use to display a single value from your database. For example, this will display the number of users on your site: 
[sqlgetvar]SELECT COUNT(*) FROM wp_users[/sqlgetvar] 
Note: because of a known exploit in the WordPress shortcode functionality it is required that an admin user create an SQL Report with the exact query that will be used in the sqlgetvar shotcode, otherwise any subscriber could white their own shortcode query.
If you want to include an “Export to CSV” button on your page or post then use the additional shortcode [SQLEXPORTCSV] once on any page or post that contains a report you want visitors to be able to download. Thanks to @loristictok and @rob66bnu for posting the suggestion with the JavaScript that I used to make this new Shortcode. 
Note: Adding this shortcode to the just one time will insert the “Export to CSV” button at the top of every HTML Table on the page.
<h4>Automatic Database Backups</h4>
Your database can be automatically saved and archived every hour and/or every day, and backups can be emailed to the address you specify. You can also restore the data to your WP DB or an external DB, which makes copying your database to another server and easy task.

EZ SQL Reports Shortcode Widget and DB Backup

Create and save SQL Reports in your WP Admin and place them on pages and posts with a shortcode. Keep your database safe with automatic backups.

Roy Orbitson

<a href="https://www.adminer.org/" rel="nofollow ugc">Adminer</a> is a database administration tool that allows viewing and editing of databases tables, routines, triggers, etc. It also allows running SQL statements to import data, make bulk changes, or perform other complex operations. It is similar in function to phpMyAdmin. It is intended for use by developers and those who have had experience with databases.
This plugin provides a secure connection to your WordPress database, limited to that which is saved in your WordPress configuration, and access is granted only to logged-in accounts that possess the <code>edit_plugins</code> capability (normally admins). This ensures it can only used by those who already have enough privilege to pose a risk to the installation. Each and every request to Adminer will first be authenticated using your WordPress session. Some security plugins impose extra restrictions on admin sessions, so this plugin may not work if you have one installed.
Note that any other databases on the same host and protected by the same credentials will also be accessible in Adminer. This is how databases operate and not a limitation of Adminer nor this plugin. If other databases need different access restrictions, they should have separate credentials.
It comes with all the themes published in Adminer’s Git repository, so you can select a style that suits you.

Database Access with Adminer

Secure and themed, just what I need. Of course I keep this plugin disabled, and only activate when I need to debug something. As an extra protection =)

Themed!

Provides a secure interface to your WordPress database using Adminer, the popular database administration tool.

EZ SQL Reports Shortcode Widget and DB Backup vs Database Access with Adminer