I am the author of this book, I'd love to get feedback on the book. I haven't updated much in the last few months. But I am always looking to improve the book for newcomers.
For example the Result type's LastInsertId() method doesnt work in a few cases for postgres that it does for others.
Also, as far as Go language is concerned, we do not really have to worry about the underlying database, the code, as others have rightly pointed out, is totally reusable