On Friday 29 February 2008 3:49 pm, Ed Leafe wrote: > On Feb 29, 2008, at 5:10 PM, Uwe Grauer wrote: > > Maybe it helps to read another explanation. > > This was a reply from the firebird-support group: > > http://tech.groups.yahoo.com/group/firebird-support/message/92493?l=1 > > No, since they're saying the same thing. Actually, this explanation > is worse, since it says that Firebird uses the 'as' expression as an > identifier, and not a column alias. If they can use it in a GROUP BY > to refer back to the original expression, there is no reason (other > than they didn't implement it) that they couldn't provide the exact > same behavior in HAVING. > > If you cannot use the names of derived columns in a HAVING, then what > is the difference between HAVING and WHERE? > > -- Ed Leafe > >From the Postgres docs: HAVING eliminates group rows that do not satisfy the condition. HAVING is different from WHERE: WHERE filters individual rows before the application of GROUP BY, while HAVING filters group rows created by GROUP BY. Each column referenced in condition must unambiguously reference a grouping column, unless the reference appears within an aggregate function.
It's the SQL standard. This is a fight you will have to take up with the SQL committee. -- Adrian Klaver [EMAIL PROTECTED] _______________________________________________ Post Messages to: [email protected] Subscription Maintenance: http://leafe.com/mailman/listinfo/dabo-users Searchable Archives: http://leafe.com/archives/search/dabo-users This message: http://leafe.com/archives/byMID/dabo-users/[EMAIL PROTECTED]
