Mysql is great for a small or maybe medium sized company to build a dynamic website. The problem with all the MySQL and Postre folks, is that most companies you are working for will not be using MySQL or PostreSQL for their core database.
Its just does not have all the enterprise level requirements for an enterprise DB, unless perhaps, you are somehow using a MYSQL database for your web application, and synchronizing or updating its data from the main transactional database.
I do agree, though, using PHP with MySQL is great in terms of all the support and shared apps available on the web. Similiar to the ASP and MS soltuions. Unfortunately, Progress with webspeed are SERIOUSLY lacking in this area. Progress has Nusphere, which is their flavor of MySQL for a charge with some nice development tools working with PHP. This still doesnt resolve the problem for most folks developing on Progress with webspeed. I just don't understand Progress sometimes. In silicon valley their a complete unknown especially in terms of a database for developing web applications. This means bad integration with some of the largest software companies that develop tools and apps that work with your database. Most of them will alaways have easy integration with Oracle, DB2, SQL2000. You ask them if they support Progress, and they'll reply back saying:
"Progress who?"