A typical installation of WordPress usually has MySQL database as the backend, recently I found a need to reset the password for multiple users in one go. Here is how it was achieved.
First install MYSQL Workbench on the required machine. MySQL Workbench can be downloaded here.
Identify the database and the connection string details from the wp-config.php file.
Connect to the database from within MYSQL Workbench as listed here.
Once connected look for the table wp_users in the database.
In a new query windows execute the below query to reset a single or multiple rows password as required.
UPDATE wordpress746.wp_users SET user_pass = MD5('NewPassword') WHERE length(user_login) = 4
e.g. in this case I reset the password for all users who have a four letter username.
And that’s it !!