mysql> update mysql.user set authentication_string=password('1qaz@WSX') where user='root';
Query OK, 1 row affected, 1 warning (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 1
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
mysql>
mysql>
mysql> quit;
Bye