Joe Celko's Trees and Hierarchies in SQL for Smarties, Second Edition (The Morgan Kaufmann Series in Data Management Systems)
Joe Celko served 10 years on ANSI/ISO SQL Standards Committee and contributed to the SQL-89 and SQL-92 Standards.Mr. Celko is author a series of books on SQL and RDBMS for Elsevier/MKP. He is an independent consultant based in Austin, Texas.He has written over 1200 columns in the computer trade and academic press, mostly dealing with data and databases.