Ed Wagner (10/3/2015)
I worry if the stuff above is what they're teaching on the site you're using.
I took a peek at the khanacademy site...holy cow the sql stuff is hideous. Anybody wanting to learn sql would be better off walking away from that place immediately if not sooner. It is free and horribly overpriced. There is no way I would recommend using that place and would strongly urge people to run away screaming.
As with many things you get what you pay for.
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