I think Jonah is referring to the the 'START WITH ... CONNECT BY'
clause feature from Oracle. Am I right Jonah?
For such queries, Oracle introduces a pseudocolumn LEVEL, that
holds the value of the indentation level of the current rusultant row.
In Oracle, the LEVEL column returns 0 for the root node of a
hierarchy, 1 for it's children, 2 for their children, and so forth.
LEVEL is commonly used to indent hierarchical results.
LEVEL might not be a part of the standard, but it is very handy
when dealing with hierarchical queries.
The chapter 1 (http://www.oreilly.com/catalog/sqlpr/chapter/ch01.pdf)
of book 'SQL Pocket Guide' elaborates more on it.
Gurjeet.
On 5/16/06, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> Perhaps you should start by explaining what the heck you're talking
> about ;-). I can find nothing in the SQL2003 spec that sounds anything
> like a LEVEL function or pseudocolumn.
>