Re: syntax for access an alias in the where clause ?

Поиск
Список
Период
Сортировка
От Jeff Eckermann
Тема Re: syntax for access an alias in the where clause ?
Дата
Msg-id 20020619220427.58854.qmail@web20810.mail.yahoo.com
обсуждение исходный текст
Ответ на syntax for access an alias in the where clause ?  (Michael Agbaglo <byteshifter@shifted-bytes.de>)
Список pgsql-sql
The WHERE clause is evaluated before the SELECT list,
at which point the value of "[alias 1]" is not known. 
You will need to use "[expression 1]" there instead.

ORDER BY is evaluated after the SELECT, so "[alias 1]"
can be used there with no problems.

--- Michael Agbaglo <byteshifter@shifted-bytes.de>
wrote:
> Hi !
> 
> It's long ago since I used SQL :-)
> 
> select [expression 1] as [alias 1], [expression 2]
> as [alias 2]
> where [alias 1] < [alias 2]
> order by [alias 2] - [alias 1]
> 
> ---> ERROR:  Attribute '[alias 1]' not found
> 
> I found a lot of 'select [expression] as' but I've
> never seen somebody 
> accessing the alias ... Can't this be done ?
> 
> M.
> 
> 
> 
> 
> ---------------------------(end of
> broadcast)---------------------------
> TIP 1: subscribe and unsubscribe commands go to
majordomo@postgresql.org


__________________________________________________
Do You Yahoo!?
Yahoo! - Official partner of 2002 FIFA World Cup
http://fifaworldcup.yahoo.com


В списке pgsql-sql по дате отправления:

Предыдущее
От: Tom Lane
Дата:
Сообщение: Re: syntax for access an alias in the where clause ?
Следующее
От: Stephan Szabo
Дата:
Сообщение: Re: syntax for access an alias in the where clause ?