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From Thomas Nielsen <Thomas.Niel...@Sun.COM>
Subject Re: Derby Equivalent of MySql queries
Date Thu, 22 Nov 2007 18:04:30 GMT
Hi Aneez,

The LIMIT syntax is not part of the SQL standard (yet at least...), and 
may as such be considered a MySQL dialect.

Derby does not support LIMIT, but we are working on implementing.the 
approach taken in the SQL standard using the ROW_NUMBER() function for 
the upcoming 10.4 release.You can find some more infromation on this 
exact topic at
   http://wiki.apache.org/db-derby/OLAPRowNumber

If you need to do this, I regret to say you need to do programatically 
in the java application as of Derby 10.3. This is also regrettably what 
happens when application programmers rely on non-portable SQL (or any 
other non-standard, non-portable functionallity for that matter).

There is a good comparison write-up of different databases and their 
support for similar functionallity here:
   http://troels.arvin.dk/db/rdbms/#select-limit

BR,
Thomas

Aneez Backer wrote:
> Hi
>
> The tables are being used for dynamic update and count of notification 
> whenever a  pre-defined change is made in any of the columns. Also, I 
> had posted the trigger statement in a simplified form omitting data 
> from it for which I knew I could work on myself.
>
> Hope that answers your query.
>
> Can you help me with one more transformation??
>
> select * TABLEA where uid in (101,102,103) order by creation_time limit 5"
>
> The problem here is with the 'limit 5' part of the query
>
> Also, can you let me know of any online tutorial help available for 
> learning Derby Query basics ??
>
> Thanks
> -aneez
>
> */"Bernt M. Johnsen" <Bernt.Johnsen@Sun.COM>/* wrote:
>
>     Hi,
>
>     >>>>>>>>>>>> Aneez Backer wrote (2007-11-21 20:05:01):
>     > Thanks Bernt.
>     >
>     > That helped
>
>     Just a small question: Is there some special (e.g. performance)
>     requirements that force you to maintain the data in TABLEB? Since
>
>     SELECT TAGCOUNT FROM TABLEB WHERE ID=xxx;
>
>     should give the same result as
>
>     SELECT COUNT(TAG_ID) FROM TABLEA WHERE TAG_ID=xxx;
>
>     you could perhaps do without the triggers and TABLEB?
>     -- 
>     Bernt Marius Johnsen, Database Technology Group,
>     Staff Engineer, Derby/Java DB
>     Sun Microsystems, Trondheim, Norway
>
>
>
>
>
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