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: [email protected]
[mailto:[email protected]] 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: [email protected]
[mailto:[email protected]] 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: [email protected]
[mailto:[email protected]] 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: [email protected]
[mailto:[email protected]] 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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