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< [[http://umitanuki.net/pgsql/wfv08/design.html|his site]] for more details.
to
> [[http://umitanuki.net/pgsql/wfv08/design.html|his site]] for more details. There was no support for user-defined window function, but Tom believe, that 8.4 should have it. Very good.
Window function (SQL 2003) - one of the very interesting for OLAP feature previously missed in PostgreSQL was committed to the CVS HEAD by Tom Lane. Hitoshi Harada wrote proposal and made a patch, see his site for more details. There was no support for user-defined window function, but Tom believe, that 8.4 should have it. Very good.
Simply speaking, window function is an aggregate over a partitioned set of rows. Think about window moving over rows.
One of the interesting application of window function would be data smoothing.