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Posted to user@cayenne.apache.org by Andre Lomonaco <an...@gmail.com> on 2010/07/25 00:19:06 UTC

Using SQL ABS

      Hi Everyone,

      I'm newbie in Cayenne and I will apreciate if someone can help me in one question..

      I have a table with a VARIACAO Field (Type DOUBLE)         
      I can store in this Field Positive and Negative Numbers

      When I execute the following code, it's return to me first the Negative values and after the Positive values

      SelectQuery query = new SelectQuery(RiscoTotal.class);
      query.addOrdering(RiscoTotal.VARIACAO_PROPERTY,true);

       ObjectContext context = BaseContext.getThreadObjectContext();
       List<RiscoTotal> riscoTotal = context.performQuery(query);

       Return: -12.0, -6.0, 3.0, 15.0

       My questions is:

       How can I do to make a query to return only the ABS value
       I wanna receive the following results

       15.0, -12.0, -6.0, -3.0

       My Best Regards,

       Andre Lomonaco

Re: Using SQL ABS

Posted by Andrus Adamchik <an...@objectstyle.org>.

Unfortunately neither SelectQuery nor EJBQLQuery support functions in  
the ORDER BY clause (something we should probably address in 3.1). You  
have a few choices:

* Use SQLTemplate

* Map an extra attribute in RiscoTotal DbEntity as "ABS(VARIACAO)",  
then an attribute in ObjEntity connected to "ABS(VARIACAO)"  
DbAttribute. Then you can order on this fake attribute. (I know you  
can map this, but I haven't tried running queries with such mapping. I  
guess that should work).

Andrus

On Jul 25, 2010, at 1:19 AM, Andre Lomonaco wrote:

>     Hi Everyone,
>
>     I'm newbie in Cayenne and I will apreciate if someone can help  
> me in one question..
>
>     I have a table with a VARIACAO Field (Type DOUBLE)
>     I can store in this Field Positive and Negative Numbers
>
>     When I execute the following code, it's return to me first the  
> Negative values and after the Positive values
>
>     SelectQuery query = new SelectQuery(RiscoTotal.class);
>     query.addOrdering(RiscoTotal.VARIACAO_PROPERTY,true);
>
>      ObjectContext context = BaseContext.getThreadObjectContext();
>      List<RiscoTotal> riscoTotal = context.performQuery(query);
>
>      Return: -12.0, -6.0, 3.0, 15.0
>
>      My questions is:
>
>      How can I do to make a query to return only the ABS value
>      I wanna receive the following results
>
>      15.0, -12.0, -6.0, -3.0
>
>      My Best Regards,
>
>      Andre Lomonaco