No Groupby in XQuery is a pain!!

, ,
1

Hello Everyone,

I am sitting here since three hours trying to figure out how to make a simple group by in XQuery. I really don’t understand why W3C decided not implementing an Groupby into XQuery.

My Sql Statement:

SELECT
	wisc_berkeley_tracetime.rID,
	wisc_berkeley_tracelist.ip	
	
FROM
	wisc_berkeley_tracelist INNER JOIN wisc_berkeley_tracetime 		
	ON wisc_berkeley_tracelist.rID= wisc_berkeley_tracetime.rID
WHERE
	(wisc_berkeley_tracetime.dat = '20000801000000')
	GROUP by wisc_berkeley_tracelist.ip;
</pre><BR><BR>So this is the exact statement in XQuery just without Group by:<BR><BR><pre class="ip-ubbcode-code-pre">
for $tl in doc("wisc_berkeley_tracelist.xml")/data/row
for $tt in doc("wisc_berkeley_tracetime.xml")/data/row[dat='20000801000000' and rID=$tl/rID]

return 
	<ROW>
			 
		 {	$tl/ip  } 
		 {	$tt/rID  } 
		
	</ROW>




But how do I the Group by?

Best Regards

Houman Khorasani
University of Wisconsin Platteville

2

Hi,

XQuery supports grouping with the aid of the distinct-values()
function that is not yet supported with Tamino 4.1. It will
however be contained in 4.2. On how to do grouping with
distinct-values() please check appendix G2 in the W3C’s XQuery
draft, i.e. http://www.w3.org/TR/xquery/#id-grouping.

Regards,
Juliane.

3

Hi Juliane,

It’s ok I am trying it with Saxon.

Actually it really gets hard if I need to groupby within a join.

The xample in W3 Draft doesn’t explain groupby within a join.

SELECT
          wisc_berkeley_tracetime.rID,
          ip,
          min
FROM
          wisc_berkeley_tracelist INNER JOIN wisc_berkeley_tracetime           
          ON wisc_berkeley_tracelist.rID = wisc_berkeley_tracetime.rID
WHERE
          (wisc_berkeley_tracetime.ndate = '20000801000000')
          GROUP by wisc_berkeley_tracelist.ip;
</pre><BR><BR>This XQuery statement has no ?group by? on ip yet.  I am aware of distinct-value but have no idea how to use it in an efficient way on this query.<BR> <BR><pre class="ip-ubbcode-code-pre">
for $wbtl in doc("wisc_berkeley_tracelist.xml")//row,
    $wbtt in doc("wisc_berkeley_tracetime.xml")//row[dat = '20000801000000' and rID = $wbtl/rID]
return 
          <ROW>
          { 
                    $wbtt/rID, $wbtl/ip, $wbtt/min
          } 
          </ROW>



Do you have an idea how to do that?

Thanks

Houman Khorasani
University of Wisconsin Platteville

4

Hi,

let $wbttlist :=
for $wbtl in doc(“wisc_berkeley_tracelist.xml”)//row
return doc(“wisc_berkeley_tracetime.xml”)//row[dat = ‘20000801000000’ and rID = $wbtl/rID]
for $ip in distinct-values($wbttlist/ip)
return

{
for $wbtt in $wbbtlist[ip = $ip]
return

{
$wbtt/rID, $wbtt/min
}

}


Regards,
Juliane.