Re: SQL Help

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От Bruno Wolff III
Тема Re: SQL Help
Дата
Msg-id 20030530163040.GA22409@wolff.to
обсуждение исходный текст
Ответ на SQL Help  (C F <tacnaboyz@yahoo.com>)
Список pgsql-sql
On Fri, May 30, 2003 at 08:47:03 -0700, C F <tacnaboyz@yahoo.com> wrote:
> Hello,
> I already tried this same basic question with no response....  maybe I was too wordy.  So here it is simplified....
what'sthe best way to write this query?  I'm open to using stored procedures, but even then I don't know how I would
conditionallypopulate a resultset (refcursor).  Notice that in the first three cases, the expression is the exact same,
onlythe return value is different.  This seems inefficient....
 
>  
> 
> select 
>   (case when column1 = column2 then column3 end) as alias1,
>   (case when column1 = column2 then column4 end) as alias2,
>   (case when column1 = column2 then column5 end) as alias3,
>   (case when column6 = column7 then column8 end) as alias4
> from
>   mytable
> ;

That seems pretty efficient. I wouldn't expect the repeated column1 = column2
tests to add much overhead. Unless there is more to the story this looks
to be what you want to do.


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