You don't so much need to know MySQL or PHP to be successful with the dynamic suite, but you do need to have a decent understanding of how Dynamic webpages function, and how relational databases work.
An ASP /SQL site will use the same basic concepts as a PHP / MySQL site. For example, passing querystring variables from page to page to tell the database what record should be used, or using session variables to determine which user is logged in.
You will need to create the database in MySQL for the site to use, but if you can do that in MS SQL, you will be able to create a MySQL database, Same concepts, just a different GUI.