Is there any command to optimize all MySQL tables one by one automatically?

I usually use mysqlcheck with --optimize and --databases combination. mysqlcheck is a command-line interface for administrators to check, optimize and repair tables.

mysqlcheck -uroot -p --optimize --databases myDatabase

Here is the MySQL doc : http://dev.mysql.com/doc/refman/5.5/en/mysqlcheck.html

Max.

You can use information schema to generate the statements you need:

SELECT Concat('OPTIMIZE TABLE ',TABLE_NAME, ';') FROM INFORMATION_SCHEMA.TABLES 
   WHERE table_schema='yourdb';