On Fri, 09 Apr 2004 02:11:44 -0400, Tom Lane wrote: >> ROW_NUMBER() is a spec defined function. (6.10 of SQL200N) > > If the spec doesn't even have a year number yet, you can hardly expect > real implementations to support it ;-)
SQL:2003 is finished. Among its new (non-core) OLAP features are a set of "windows functions" (spec section 6.10), which include feature ID T611 (elementary OLAP): - ROW_NUMBER() OVER (...) - RANK() OVER (...) - DENSE_RANK() OVER (...) feature ID T612 (extended OLAP): - PERCENT_RANK() OVER (...) - CUME_DIST() OVER (...) See http://www.acm.org/sigmod/record/issues/0403/index.html#standards for an article which summarizes the news in SQL:2003. ROW_NUMBER() OVER may be used in queries where a PostgreSQL user which use LIMIT. RANK() OVER may be used in queries where a PostgreSQL user would have to come up with a somewhat strange query in order to get acceptable performance, see http://troels.arvin.dk/db/rdbms/#select-top-n-postgresql -- Greetings from Troels Arvin, Copenhagen, Denmark ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
