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 install_plugins 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.