A very technical book, I bought this as it is known as the 'Manual' for using Frontbase and is recommended reading. A full coverage of the SQL 92 Standard at a level that is useful but not easily 'dropped' into.
That this is how I learned to program in SQL probably says things about me. =p It's not the best place for most people to start, but it *is* an excellent reference. I just wish it'd been updated after SQL '92... =/