To create WP-admin user from backend in MySQL database and grant privileges:
===========================================================
INSERT INTO `wp_users` (`user_login`, `user_pass`, `user_nicename`,
`user_email`, `user_status`) VALUES ('mhtest', MD5('qwe123!@#'),
'firstname lastname', 'email@example.com', '0');# 1 row affected.
INSERT INTO `wp_usermeta` (`umeta_id`, `user_id`, `meta_key`,
`meta_value`) VALUES (NULL, (Select max(id) FROM wp_users),
'wp_capabilities', 'a:1:{s:13:"administrator";s:1:"1";}');# 1 row
affected. INSERT INTO `wp_usermeta` (`umeta_id`, `user_id`, `meta_key`,
`meta_value`) VALUES (NULL, (Select max(id) FROM wp_users),
'wp_user_level', '10');# 1 row affected.
--------------------------------------------------------------------
