In my last post I made it a point to demonstrate that a ratio would better show my expertise than an absolute number. In that post I also alluded to such a simple concept as “book” being possibly vague in a larger sense than what is realized by the concretization of the term “book” in the form of ISBN. Of course those in the know know that an ISBN only uniquely identifies an edition of a title, a title being that part of the cover we are judging our books by. The cover in turn being the thing between which the pages of writing are presumed bound (or at least sorted). While my logic may at this point seem a bit meandering, please, bear with me.

An ISBN uniquely identifies a title and not in the sense that it uniquely identifies an instance of a title that may be on a particular cover. So it might stand to reason that more than one book may have the same title, book again in this case being less a synonym for title and more an intance of it. Now from the point of view of expertise this does little for our sumarization but it does broach the topic of said expertise and begs the question as to why we might have more than one copy of Itzik Ben-Gan’s Microsoft SQL Server 2012 High Performance T-SQL Using Window Functions (ISBN 978-0-7356-5836-3),  which we don’t, but we might and we might want to know which if any of the other books contributing to this library of expertise we might have more than one copy of, as we might want to sell them or trade them or what have you.

The phrase (we’ll call these queries going forward) that might tell us how many titles we have more than one of might look something like: