Show current user list:

mysql> SELECT user, host, plugin FROM mysql.user;

Add new user:

mysql> CREATE USER '<new_username>'@'<host>' IDENTIFIED BY '<new_password>';

Where:

<new_username> is unique new username to create/add.

<host> is the hostname or IP address of host where user will login from.  If local, use 'localhost'.

<new_password> is the new password for <new_username>.

NOTE:  Username is actually a combination of  '<new_username>'@'<host>', such as 'user'@'localhost'.

After adding user run: 

mysql> FLUSH PRIVILEGES;

To change user password:

mysql> ALTER USER '<username>'@'<host>' IDENTIFIED BY '<new_password>';

Where:

<username> is the username to change the password.

<host> is the hostname or IP address of host where user will login from.  If local, use 'localhost'.

<new_password> is the new password for <new_username>.

NOTE:  Username is actually a combination of  '<username>'@'<host>', such as 'user'@'localhost'.

To remove/delete a user from MySQL:

mysql>  DROP USER '<username>'@'<host>';

Where:

<username> is the username to change the password.

<host> is the hostname or IP address of host where user will login from.  If local, use 'localhost'.

NOTE:  Username is actually a combination of  '<username>'@'<host>', such as 'user'@'localhost'.

To See Access Levels for User:

mysql> SHOW GRANTS FOR '<username>'@'<host>';

Where:

<username> is the username to see the list of access this user has.

<host> is the hostname or IP address of host where user will login from.  If local, use 'localhost'.

NOTE:  Username is actually a combination of  '<username>'@'<host>', such as 'user'@'localhost'.

To Add Permissions to User:

mysql> GRANT <ACCESS>,<ACCESS> ON <database>.* TO '<username>'@'<host>';

Where:

<ACCESS> is type of access or privilege to add to this user. To add more than one, add them separated by comma.

<username> is the username to add access.
<database> is the specific database for user access.  For all databases use asterisk(*).

Example: Grant DML access (select/insert/update/delete)

mysql> GRANT SELECT, INSERT, UPDATE, DELETE ON <database>.* TO 'user'@'localhost';

Example: Grant Read-only

mysql> GRANT SELECT ON <database>.* TO 'user'@'localhost';

Example: Grant all privilege (ADMIN RIGHTS) to user:

mysql> GRANT ALL PRIVILEGES ON *.* TO 'admin'@'localhost' WITH GRANT OPTION;

To Remove/Revoke Permissions to User:

mysql> REVOKE <ACCESS>,<ACCESS> ON <database>.* FROM '<username>'@'<host>';

NOTE: Not REVOKE  "TO" user, but REVOKE  "FROM" user.

Where:

<ACCESS> is type of access or privilege to remove/revoke from this user. To revoke more than one, add them separated by comma.

<username> is the username to remove access from
<database> is the specific database for user access.  For all databases use asterisk(*).

NOTE:  Username is actually a combination of  '<username>'@'<host>', such as 'user'@'localhost'.

Example: Revoke ALL privilege from user:

mysql> REVOKE ALL PRIVILEGES ON *.* FROM 'user'@'localhost';

1. Create test database, testdb:

mysql> CREATE DATABASE testdb;

2. Switch or make database active for work

mysql> USE testdb;

3. Create first database table (empty), users, for testdb:

mysql> CREATE TABLE users (id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(100), email VARCHAR(100), created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP);

4. Add mockup data to table, users:

mysql> INSERT INTO users (name, email) VALUES ('Alice', 'alice@example.com'), ('Bob', 'bob@example.com'), ('Charlie', 'charlie@example.com');

5. Add additional data to table, users:

mysql> INSERT INTO users (name, email) VALUES ('Dale', 'dale@example.com'), ('Edgar', 'ed@example.com'), ('Fred', 'fred@example.com');