Fabricio Carella

This plugin will allow you to execute any type of SQL query into the WordPress’s DB connecting through the driver provided by the MySQLi extension without the need to use another tool like phpMyAdmin.
It also gives you the ability to export the results in a CSV format file.
In order to access this plugin’s admin page (Tools -> Run SQL Query), your account needs to have the <code>install_plugins</code> capability, that means a Super Admin in the multi-site installation or an Admin in a single site.
Feel free to contribute: 
https://github.com/Sefirost/run-sql-query
Use on you own risk. Under no circumstances will the Author of this plugin assume responsibility or liability for any damages or destructive effects on the database resulting from the queries executed using this tool.

Run SQL Query

Run SQL Query is a simple plugin to quickly execute any type of SQL query into the WordPress's DB and export the results in a CSV format file.

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.

Run SQL Query vs Database Access with Adminer