How to get the size of databases in MySQL

Sometimes a DB in MySQL grows without alerting the sysadmin and in this case it is helpful to have a query to identify the real dimension.

A query to get the size and free space of MySQL DB is:

SELECT table_schema "Data Base Name", 
sum( data_length + index_length ) / 1024 / 
1024 "Data Base Size in MB", 
sum( data_free )/ 1024 / 1024 "Free Space in MB" 
FROM information_schema.TABLES 
GROUP BY table_schema ;