how to show the permissions for a user in mysql code example

Example 1: mysql users and permissions

-- Grants list
SELECT * FROM information_schema.user_privileges;
SELECT CONCAT('SHOW GRANTS FOR ''',user,'''@''',host,''';') FROM mysql.user;

-- Grant a user
/*  ALL PRIVILEGES  All privileges
    CREATE          Create databases and tables
    DROP            Drop databases and tables
    DELETE          Delete rows from a specific table
    INSERT          Insert rows into a specific table
    SELECT          Read a database
    UPDATE          Update table rows   */
GRANT SELECT, UPDATE ON db_name.table_name TO 'my_user'@'localhost';
GRANT SELECT ON *.* TO 'my_user'@'localhost';
GRANT ALL PRIVILEGES ON db_name.* TO 'my_user'@'localhost';

--Display user grants
SHOW GRANTS FOR 'my_user'@'localhost';

Example 2: mysql user permission database

GRANT ALL PRIVILEGES ON `db_name`.* TO 'user'@'host'