[MarkLogic Dev General] Can an xquery order by clausebeconstructed?

[Michael Blakeley]

Danny pointed out that I pasted the wrong link: sorry about that.

http://markmail.org/thread/rpc3unlqlj72loah

-- Mike

On 2009-05-22 11:11, Michael Blakeley wrote:
> http://lists.marklogic.com/thread/rpc3unlqlj72loah
>
> Using a static approach gets much more complex as you add more fields.
>
> -- Mike
>
> On 2009-05-22 10:35, McBeath, Darin W (ELS-STL) wrote:
>> Tim.
>>
>> I can get the following to work when ordering by a ‘single’ field.  If you need to sort on multiple fields, I could not get that to work … I would get a syntax error.
>>
>> But, if you need to sort on multiple fields, then you may need to use xdmp:value() … or you could also use xdmp:eval().  They are fairly similar … one distinction is that the ‘current context’ namespaces, variables etc. are readily available when using xdmp:value (in other words you don’t have to redeclare namespaces, etc.).  So, I believe that is the more preferable approach nowadays.
>>
>> let $test :=<entries>
>>                 <entry>
>>                  <a>darin</a><b>darby</b>
>>                 </entry>
>>                 <entry>
>>                  <a>darby</a><b>darin</b>
>>                 </entry>
>>                 </entries>
>>
>> for $x in $test/entry
>> let $a := $x/a
>> let $b := $x/b
>> order by  if (true()) then $b else $a
>> return
>>     $x
>> ________________________________
>> From: general-bounces at developer.marklogic.com [mailto:general-bounces at developer.marklogic.com] On Behalf Of Tim Meagher
>> Sent: Friday, May 22, 2009 1:26 PM
>> To: 'General Mark Logic Developer Discussion'
>> Subject: RE: [MarkLogic Dev General] Can an xquery order by clausebeconstructed?
>>
>> Hi Danny,
>>
>> Hmm – I’m not sure how to use the xdmp:value() function in this case, plus I’ve tried to dynamically construct the OrderByClause with one or 2 sort elements and an OrderSpec as well.  Do you have any examples?
>>
>> Thanks,
>>
>> Tim
>>
>> ________________________________
>> From: general-bounces at developer.marklogic.com [mailto:general-bounces at developer.marklogic.com] On Behalf Of Danny Sokolsky
>> Sent: Friday, May 22, 2009 1:03 PM
>> To: General Mark Logic Developer Discussion
>> Subject: RE: [MarkLogic Dev General] Can an xquery order by clause beconstructed?
>>
>> Each “orderspec” is an expression, and the expression can be any XQuery expression (for example an if/then/else):
>>
>> http://www.w3.org/TR/xquery/#prod-xquery-OrderByClause
>>
>> This will work for many things, but not if you want to manipulate more than the expression.  But you can get a long way with if/then/else.
>>
>> If you want to do something more complex, then David’s xdmp:value suggestion is a good one, where you construct a string that is your new flwor expression and evaluate it with xdmp:value.
>>
>> -Danny
>>
>> From: general-bounces at developer.marklogic.com [mailto:general-bounces at developer.marklogic.com] On Behalf Of David Steiner
>> Sent: Friday, May 22, 2009 8:51 AM
>> To: General Mark Logic Developer Discussion
>> Subject: RE: [MarkLogic Dev General] Can an xquery order by clause be constructed?
>>
>> You could always construct the entire for clause as a string and pass it to xdmp:value(…).
>> The MarkLogic folk probably have a better solution though.
>>
>> From: general-bounces at developer.marklogic.com [mailto:general-bounces at developer.marklogic.com] On Behalf Of Tim Meagher
>> Sent: Friday, May 22, 2009 8:16 AM
>> To: 'General Mark Logic Developer Discussion'
>> Subject: [MarkLogic Dev General] Can an xquery order by clause be constructed?
>>
>>
>> Hi folks,
>>
>>
>>
>> I would like to know if the order by clause can be programmatically constructed. For example, given a query such as the following:
>>
>>
>>
>> for $el in cts:search(xdmp:directory("/SomeDir/","infinity")/SomeNode,
>>
>>     cts:element-value-query(xs:QName("SomeElement"), "SomeElementValue",
>>
>>     ("case-insensitive", "punctuation-insensitive", "diacritic-insensitive")))
>>
>>
>>
>>     let $id := string($e/@ID)
>>
>>     let $author := string($el/author[1])
>>
>>     let $title := string($el/title[1])
>>
>>
>>
>>     order by $id, $title, $author
>>
>>
>>
>>     return $el
>>
>>
>>
>> I would like to be able to programmatically construct the order clause to be something like "$author, $title" instead of "$id, $title, $author".
>>
>>
>>
>> Thank you!
>>
>>
>>
>> Tim – aaom consulting
>>
>>
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