Valid characters
MySQL, MySQL, MySQL, MySQL, MySQL, MySQL
Identifiers can consist of basic Latin characters, numbers 0-9, $ and underscores. They can begin with a number, but cannot consist only of them.
Register
In order to avoid problems in names with different register, it is best to accept a consistent agreement, for example, always create and reference databases and tables using string names. This agreement is recommended for maximum portability and ease of use.
Also
How table and database names are stored on disk and used in MySQL depends on the system variable lower_case_table_names , which you can set when you start mysqld .