How to DROP MySQL users manually

Introduction

There are times where you may need to DROP a MySQL user manually to address an issue or correct a problem caused by lingering users in the MySQL.user table. 

Procedure

The easiest way to perform this is via the MySQL command line:

mysql mysql -e "DROP user '$USER'@'$HOST';"

Be sure to replace $USER with the appropriate user and $HOST with the appropriate host. For the host, this will generally be "localhost".  Additionally, be sure to leave the (') single-quotes around the user and the host.

For example:

mysql mysql -e "DROP user 'cptech'@'localhost';"

If you need to perform this operation for all the users in an account you may use this command:

mysql mysql -e "delete from mysql.user where User like 'cptech%';"

And this command to remove them from the db table:

mysql mysql -e "delete from mysql.db where User like 'cptech%';"

For more details, you may refer to MySQL's official documentation here.