db-derby-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From d...@apache.org
Subject svn commit: r634587 - /db/derby/docs/trunk/src/ref/rreffuncrownumber.dita
Date Fri, 07 Mar 2008 08:53:59 GMT
Author: dyre
Date: Fri Mar  7 00:53:58 2008
New Revision: 634587

URL: http://svn.apache.org/viewvc?rev=634587&view=rev
Log:
DERBY-2998: Add support for ROW_NUMBER() window function
Additional documentation for ROW_NUMBER.
Patch contributed by Thomas Nielsen
Patch file: d2998-followup-doc3.diff

Modified:
    db/derby/docs/trunk/src/ref/rreffuncrownumber.dita

Modified: db/derby/docs/trunk/src/ref/rreffuncrownumber.dita
URL: http://svn.apache.org/viewvc/db/derby/docs/trunk/src/ref/rreffuncrownumber.dita?rev=634587&r1=634586&r2=634587&view=diff
==============================================================================
--- db/derby/docs/trunk/src/ref/rreffuncrownumber.dita (original)
+++ db/derby/docs/trunk/src/ref/rreffuncrownumber.dita Fri Mar  7 00:53:58 2008
@@ -29,7 +29,8 @@
 <section> <p>The ROW_NUMBER function does not take any arguments, and for each
row over the window returns an ever increasing BIGINT. It is normally used to limit the number
of rows returned for a query. The LIMIT keyword used in other databases is not defined in
the SQL standard, and is not supported.</p>
 <p>NOTE:<ul>
 <li>Derby does not currently support the named or unnamed window specification to be
specified in the <codeph>OVER()</codeph> clause, but requires an empty parenthesis.
This means the function is evaluated over the entire resultset.</li>
-<li>ROW_NUMBER can currently not be used in a WHERE clause</li>
+<li>ROW_NUMBER can currently not be used in a WHERE clause.</li>
+<li>Derby does not currently support ORDER BY in subqueries, meaning there is currently
no guarantee for ordering of rows in the subquery SELECT. An optimizer override can be used
to force the optimizer to use an index ordered on the desired column(s) if ordering is a firm
requirement.</li>
 </ul></p>
 <p>The data type of the returned value is a BIGINT number.</p> 
 </section>



Mime
View raw message