Windowing features in PostgreSQL 8.4

PostgreSQL recently added a whole bunch of mini-analytic features in version 8.4. It also happens to be Turing complete with support for recursion. Ha! Recursion in SQL...

To me, the most interesting feature was the introduction of the partition by and related clauses. I remember using this feature in Oracle 10g in 2005, which I think was part of the Analytics package if I'm not mistaken. It's important to me because this is what inspired me in some way to start working on StreamCruncher and explore other Windowing concepts that are now standard in any Event Stream Processing product.

SELECT key, SUM(val) OVER (PARTITION BY key) FROM tbl;