Okay, I have this book, "Teach Yourself SQL in 21 Days, 4th Edition" and it's driving me nuts. It's just sloppily written overall. The inconsistency between the SQL statements and the MySQL statements is driving me nuts. An perfect example is when they introduce the Substring function. Rather than using the MySQL substring function, the authors decided to complicate things by using the mid() function and tossing a small disclaimer at the bottom saying "oh, by the way, we used this one instead, even though mid() and substring do the same thing" Leaving me wondering, "Why are you doing this? please, let's keep things on the same track for the sake of sanity and clarity! If anything mention the mid() function as a bit of trivia!" I don't want people to get the wrong idea and think I just don't understand it, but I read the book and just wonder aloud why the authors felt compelled to make things more complicated. Did they think it would make them sound smarter? Avoid this book at all costs, or purchase and read with careful consideration.