Re: reference to 'as' field

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От Michael Fuhr
Тема Re: reference to 'as' field
Дата
Msg-id 20050901180041.GA42660@winnie.fuhr.org
обсуждение исходный текст
Ответ на reference to 'as' field  (Frank Bax <fbax@sympatico.ca>)
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On Thu, Sep 01, 2005 at 11:11:59AM -0400, Frank Bax wrote:
>
> When I use "select (f1+f2+f3+f4+f5) as f0 ..." in 7.4.3, it seems I can use
> "f0" is "order by", but not "where" clause [column 'f0' does not
> exist]?  Does this change in more current versions?  Is there a list of
> which clauses support this syntax in which versions?

Here's an excerpt from the SELECT documentation for 8.0 (8.1beta
says the same thing):

"Using the clause AS output_name, another name can be specified for
an output column.  This name is primarily used to label the column
for display.  It can also be used to refer to the column's value
in ORDER BY and GROUP BY clauses, but not in the WHERE or HAVING
clauses; there you must write out the expression instead."

http://www.postgresql.org/docs/8.0/static/sql-select.html

--
Michael Fuhr

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