using window functions

Hi,

I'm trying to get an advance taste of the window function feature that I believe is supposed to be in 8.4. I'm running 8.4devel snapshot (dated Jan-01 which seems kind of old) grabbed from the snapshot page on the postgresql website.

When I try a simple query "select avg(my_int) over (order by my_int rows unbounded preceding) order by 1;" I get an error:

ERROR: syntax error at or near "over"

Do I have to build from source to try window functions?

Thank you,

Daniel

_________________________________________________________________
Windows Live™: Life without walls.
http://windowslive.com/explore?ocid=TXT_TAGLM_WL_allup_1a_explore_032009