The funny thing is, I always thought SQL was very easy to understand, at least enough for basic use, which will carry you a long way. It's very clean and logical and conforms well to my intuitive concept of object relationships. Sure I've had frustrating moments trying to comprehend some hideous join or wondering why some query doesn't work but I never thought SQL itself was particularly hard to get started with.

Map/reduce, though, that will do your head in! It's like changing from procedural to functional programming. To me, it's much harder and far less intuitive. So I can't imagine how anyone could think using M/R is somehow easier than learning SQL. Anyone who thinks that is in for a nasty surprise. It's like claiming Erlang is easier to learn than Ruby.