SQL has been seen by many as a standard and on paper they are right. In the real world they are far from the truth when you try to make applications work on multiple databases. Who doesn’t remember ODBC as the golden bullet to solve all your database access issues and later on the same with JDBC. Luckily the language has been standardized is 1986 for the first time and they now are working on the 2008 revision which can be bought from ISO if you want to implement this free standard.
But who implements this standard? MySQL, Oracle, Sybase, PostgreSQL, MS-SQL? The question may be more like “who implements what?” and “how?”. Bug 18078 may give a hint in how well vendors are implementing SQL and may give an inside on how big the vendor lock-in really is. But is also gives an inside on how developers are wasting time writing and discussing abstraction layers to let there application like MediaWiki for example run on multiple databases.
Is this the new barrier where the FOSS-community needs to spend time to give proprietary vendors a run for there money? Just like Mozilla pushed Microsoft to accept open standard for the web, or like OASIS did with OpenDocument, or like the XMPP Standards Foundation is doing with instant messaging? Yes, AOL is running to get there AIM/ICQ-network migrated to XMPP so they can compete and communicate with Google Talk. Hopefully time will teach us how we can free us from proprietary only solutions and level the field again. Until then it’s something to work on and check for when using new applications.