[zasdffaa]

I don't want to diss this, it's useful to some but to say "Your database knowledge is outdated" is presumptuous to the point of insulting. It's basic to intermediate level stuff, like using CTEs to break up queries (and you don't discuss how this can overload the optimiser), and doing multiple aggs in one select.

I also can't C&P from your pages as they're images, but Ghost Conditions Against Unindexed Columns has '... AND type = in (3, 6, 11)' - is that right or did you mean 'type in (...)'. It also talks about multi-col indexes as being more useful in some cases, true, but very elementary.

This is good and well done, but please don't oversell it.