While I know very little about MySQL, I was surprised by that example too. How a relational join could be slower than that couple of query's? Moreover, at first

While I know very little about MySQL, I was surprised by that example too. How a relational join could be slower than that couple of query's? Moreover, at first glance, why didn't do exactly the same with a subselect(MySQL supports them now, right)? The second query seems to me a performance killer (dynamic by nature, has to be parsed every time).