Start Tableau and under Connect, select MySQL. For a complete list of data connections, select More under To a Server. Then do the following:

• Enter the name of the server that hosts the database.
• Enter the user name and password.
• Select the Require SSL option when connecting to an SSL server.
• (Optional) Select Initial SQL to specify a SQL command to run at the beginning of every connection, such as when you open the workbook, refresh an extract, sign in to Tableau Server, or publish to Tableau Server. For more information, see Run Initial SQL.
• Select Sign In.
• If Tableau can't make the connection, verify that your credentials are correct. If you still can't connect, your computer is having trouble locating the server. Contact your network administrator or database administrator.

Link: http://onlinehelp.tableau.com/current/pro/desktop/en-us/examples_mysql.html