I've been working in SQL Server for about 8 years
Where I am now, when I came in 1.5 years ago, they had queries that were taking 60 minutes to run that I got down to about 20 seconds.

They had no idea about the difference between logical and physical design, fragmentation or indexes.

I used Fox to prototype and develop a server database maintenance application.
Used Visual MaxFrame.

Then re-wrote the back-end in SQL Server 2000.

A lot of what you learn in Fox is transferable to SQL

In fact, with SQL 2005 and 2008 are more and more like Fox.