Things happened, and I am getting off to a late start. I just got back home from teaching on a Royal Caribbean Cruise ship. No, not databases; Texas-42. To answer the next question: it is a domino game played only in Texas which resembles Auction Whist (Google it at www.pagat.com). I have more talents than you thought.
My last book was TREES & HIERARCHIES IN SQL and it was recently featured in the Computer Direct Bookclub selections. The title pretty well explains the topic. My first thought was that such a narrow topic would not be a good book, but I kept finding more and more material on it. I also kept getting questions about tree structures in the newsgroups and my emails at a steady rate.
This leads to my first question: is there a need for such short, specialized SQL books? And if so, what are the topics?
1) Temporal Queries in SQL: Rick Snodgrass did an excellent book on temporal queries in SQL that went out of print, but which is available on his website at the University of Arizona in .pdf format. Chris Date also did a book on temporal queries which used a non-standard language of his own invention and a temporal model which is not popular in either the research community nor in actual products. It is out of print.
2) OLAP in SQL: There are books for particular OLAP products, but the SQL-99 Standard added CUBE, ROLLUP, extensions to GROUP BY, and the OVER() clause. These things are appearing in actual SQL products (DB2, Oracle, SQL Server, etc) now, so I could stick to my rule about only writing Standard SQL.
3) Procedural Code in SQL: While each vendor is still locked into their own 3GL/4GL language for stored procedures and triggers, there is a SQL/PSM Standard, which was covered (but in depth) by Jim Melton in his out-of-print book. There are implementations in Mimer and DB2, but not in other products.
4) Something I don't see.
I have two books due out this year. One is on SQL PROGRAMMING STYLE, which is based on the books we had in the early days of Strucutred Programming. It has formatting rules, hueristics, tips on how to think in sets, etc. The idea was a book guide that can help the Newbie get over the learning hump when they first get to SQL and are still "speaking with the syntax and programming model of their native tongue" instead of real SQL.
The other book is the third edition of SQL FOR SMARTIES. I updated what was there, added new stuff, and re-wrote code to take advantage of the SQL-92 and SQL-99 stuff that is now widely available. In short, you need to buy a new copy :)