how to: refer to select list calculations other places in the calculations.

Hi,
I have very complex sql (generated by cognos) I'm porting from Teradata that basically uses column alias in the calculated columns.
Is there any way to do this type of thing in Psql?

Essentially I need to do is refer to a calculated column later in the select list (but far more complex - like 50 pages printed out)
sel a,b,a+b as c, c*d, c*f, c*g, c*h, c*I, c*j, c*k,...... --- where c is a calculated column used in other calculations.
from ....

Doug Little
Sr. Data Warehouse Architect | Enterprise Data Management | Orbitz Worldwide
500 W. Madison, Suite 1000 Chicago IL 60661| Office 312.260.2588 | Fax 312.894.5164 | Cell 847-997-5741
Douglas(dot)Little(at)orbitz(dot)com<mailto:Douglas(dot)Little(at)orbitz(dot)com>

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