Re: ordering by multiple columns

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От Andreas Kretschmer
Тема Re: ordering by multiple columns
Дата
Msg-id 20070314161235.GB3930@KanotixBox
обсуждение исходный текст
Ответ на ordering by multiple columns  ("Pablo Barrón" <amentoraz@gmail.com>)
Список pgsql-sql
Pablo Barrón <amentoraz@gmail.com> schrieb:

> 
>  Hi!
> 
>  I'm trying to order a list in which the first parameter to order is a specific
> field, and the second should vary depending on a specific condition. More
> explicit, I would like to do something like:
> 
>  - ORDER BY a.column1, [b.column2 if c.value != 19 || c.column2 if c.value==19]
> 
>  That is to say, use a column if a value on each row isn't 19, OR use a
> different column if it isn't. How could I solve this? I've got to have a global

You can do something like this:

order by a.column1, case when c.value != 19 then b.column2 else c.column2 end;


*untested*, but the way is to use a case when <condition> then ... else
... end; - construct.


Andreas
-- 
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