January 1, 2011
I was a bit excited to see the chapter discussing analytic functions in the book “Pro Oracle SQL”, which has a rather extensive coverage of most of Oracle Database’s analytic functions (something that I have not seen from other SQL books). That chapter is very well assembled, with easier to understand descriptions of the various functions than what is found in the Oracle documentation.
However, there is one particular statement in the chapter that made be stop and think for a moment, and then ask “What, if anything, is wrong with this quote” from page 227 of the book:
“The default windowing clause [of analytic functions that support the windowing clause] is rows between unbounded preceding and current row. If you do not specify a window, you’ll get the default window. It is a good approach to specify this clause explicitly to avoid ambiguities.”
Before you answer, check the Oracle Database 11.2 documentation:
“If you omit the windowing_clause entirely, then the default is RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW.”
The Oracle Database documentation is stating essentially the same thing as the book.
What, if anything, is wrong with this quote (or the quote from the documentation)?