I really don't know if being an expert is even required for 95% of jobs.

What would you call the level you reach once you are able to understand how to interpret, and modify expertly written examples from this website.

I mean, there are a lot of people who say they are an expert at SQL and barely know how to perform a join or just know the basics of INSERT, UPDATE , etc. But take me for example, I've just spent 3 years 'porting' myself over to the paradigm that is SQL development. I use this and other sites a lot and can produce some pretty good stuff, but I would hardly consider myself an expert - just a competent builder tweaking the experts plans to suit my own household requirements.

I might even fail a 'test' in an interview if they wanted me to write something of the top of my head that involves some of the more exotic SQL.