On May 19, 2009, at 11:29 PM, Andy Colson wrote:
I'm not sure what this will do:HAVING COUNT(fxr.currency_code_quote) = 1 The only time I have ever used HAVING is like: select name from something group by name having count(*) > 1 to find duplicate name's.
That will leave out all results of multiple rows from the group by, which is not the desired result I think. IIUC the desired result is to leave out duplicates after the first match, not to leave out all results that have duplicates.
I think you want something like: HAVING effective_from = MAX(effective_from)
Or you ORDER BY effective_from DESC and use DISTINCT ON to ignore the duplicates after the first match (which is the newest currency due to the ordering).
I wonder whether it's possible to have effective_from dates in the future though, that would complicate things slightly more...
Alban Hertroys -- If you can't see the forest for the trees, cut the trees and you'll see there is no forest. !DSPAM:737,4a133d4d10091830814072! -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
