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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