From: | "Robert J(dot)C(dot) Ivens" <robert(at)roclasi(dot)com> |
---|---|
To: | Leif Biberg Kristensen <leif(at)solumslekt(dot)org> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Using column aliasses in the same query |
Date: | 2011-04-17 11:30:48 |
Message-ID: | D4619301-320C-40E6-961F-25DE26785E1B@roclasi.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
On 17 apr 2011, at 13:21, Leif Biberg Kristensen wrote:
> On Sunday 17 April 2011 13:01:45 Robert J.C. Ivens wrote:
>> Hi,
>>
>> I am not sure if there ever was a feature request for using defined column
>> aliases in the rest of a query. This would make queries with a lot of
>> logic in those aliased columns a lot smaller and this easier to
>> write/debug.
>>
>> I already know you can use the following syntax:
>>
>> SELECT col1, col2, col3, (col2-col3) as col4 FROM (SELECT col1, (long and
>> lots of logic here) as col2, col3 FROM table) s WHERE col2 < aValue
>>
>> But when you need to use (calculated) values from the actual record and or
>> have sub-selects in your main select that also need to use these values
>> things get really hairy. I don't know if the SQL specification allows it
>> but I know that RDBMS's like Sybase already support this.
>>
>> Any thoughts?
>
> It's easy to define a view or an SQL function and stash the hairy logic there.
>
> regards, Leif
True, but that is essentially the same thing as the example query I gave.
There are plenty of cases where this approach is not workable.
Cheers,
Robert
From | Date | Subject | |
---|---|---|---|
Next Message | Cédric Villemain | 2011-04-17 11:40:08 | Re: Using column aliasses in the same query |
Previous Message | Leif Biberg Kristensen | 2011-04-17 11:21:49 | Re: Using column aliasses in the same query |