SQL and Relational Theory, 3rd Edition

Footnotes

Preface to the First Edition

¹ In response to reader requests, in the third edition I’ve moved the answers that are specific to a given chapter to the end of the chapter in question and deleted the old Appendix F.

Preface to the Second Edition

² It was published in 2012.

³ In this connection, I’d like to acknowledge the contribution of a reader of the first edition, Thomas Uhren, who found an embarrassingly large number of errors. I’ll try harder in future. I promise.

⁴ Note that the name Tutorial D is always set in boldface.

Chapter 1: Setting the Scene

¹ There’s at least one pundit who doesn’t. The following is a direct quote from a document purporting (like this book!) to offer advice to SQL users: “Don’t use joins ... Oracle and SQL Server have fundamentally different approaches to the concept ... You can end up with unexpected result sets ... You should understand the basic types of join clauses ... Equijoins are formed by retrieving all the data from two separate sources and combining it into one large table ... Inner joins are joined on the inner columns of two tables. Outer joins are joined on the outer columns of two tables. Left joins are joined on the left columns of two tables. Right joins are joined on the right columns of two tables.” Your comment here.

² The standard has been through several versions, or editions, over the years. The version current at the time of writing is SQL:2011 (a formal reference for which can be found in Appendix G); the previous ...