Maybe I missed it, but I actually can't find anywhere where it says that where NOT goes. I did find all the others with not too much further looking. Really, this is just an incremental improvement we're talking about here. It is a bit strange for IN to be in the top list but not BETWEEN and second 2 is called operators not "binary and unary" operators. Note, CAST/CASE/EXISTS don't need to be in list of operators because they are completely unambiguous just like parens.