Sam Teach Yourself SQL in 21 days looks like a rough draft. In Chapter 4, a DB called 'Conversions' is used but in the examples "From Convert" is used. One cannot reference a DB by the wrong name. This occurs again in Chapter 6 on Joining DBs where a 'PARTS' DB is referred to in examples as 'PART'. There are other errors of various types. I am constantly having to error check why an example does not work. If one likes troubleshooting this is a good book to practice with. Also the index does not allow one to look up 'DECIMAL', and some other terms that would be good to reference . If the book had been adequately edited, it would be a much better book to study from.
