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.

Olar Marius

Justin Watt

Instead of needing a tool like <a href="http://www.phpmyadmin.net/home_page/index.php" rel="nofollow ugc">phpMyAdmin</a> 
or the mysql command line client to view and modify your WordPress database, 
the SQL Executioner allows you to run arbitrary SQL queries against your 
WordPress database from within the Admin. In many cases this allows you to bypass 
the inherent limitations of the WordPress Admin interface, and use the full expressive 
power of SQL to analyze and update your blog’s database.
To use simply install and visit the Tools > SQL Executioner page.
If you’re interested in contributing to the code behind this plugin, it’s also hosted on GitHub: 
https://github.com/justincwatt/wp-sql-executioner

SQL Executioner

This plugin seems to me simple but very useful.

Simple and efficient

I use this plugin on a daily basis to run quick queries in the database while developing. Very very helpful!!!

Amazing Tool

Execute arbitrary SQL queries against your WordPress database from the Admin.

EZ SQL Reports Shortcode Widget and DB Backup vs SQL Executioner