Re: AW: [xsl] XSL equivalent to SQL "unique"

Subject: Re: AW: [xsl] XSL equivalent to SQL "unique"
From: Jeni Tennison <mail@xxxxxxxxxxxxxxxx>
Date: Wed, 18 Apr 2001 16:33:14 +0100
Hi Oliver,

> Perhaps Jeni will have a break and post some explanations on how to
> solve problems like yours ;-)

Well, I'm on a break, but what could I possibly add to the solution
that you gave?

Only, I guess, that this is an example of a difficult grouping problem
where really you want to reuse the information about the *sorted*
unique values, rather than having to sort them again for every row.

This is one of those times that the node-set() extension function
really comes into its own.  So you could declare a top-level $cols
variable with:

<xsl:variable name="cols-rtf">
   <!-- get the uniquely named child elements of the set elements -->
   <xsl:for-each select="//set/*[count(.|key('cols',name())[1]) = 1]">
      <!-- sort the child elements by their name -->
      <xsl:sort select="name()" />
      <!-- create col elements to hold that information -->
      <col name="{name()}" />

<!-- turn $cols-rtf into a node set with an extension function
     (substitute prefix of your chosen processor) -->
<xsl:variable name="cols" select="exsl:node-set($cols-rtf)" />

With that, then the various xsl:for-eaches for generating the column
headers and the row data don't have to sort, they can just use the
$cols variable and the name attribute from it, e.g.

<xsl:template match="set">
      <th><xsl:value-of select="@name" /></th>
      <xsl:variable name="entries" select="*" />
      <xsl:for-each select="$cols">
            <xsl:value-of select="$entries[name() = current()/@name]" />

Of course this isn't portable. So roll on XSLT 2.0... or support for



Jeni Tennison

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