xslt show top 5 of sums

Question

long time reader, 1st time poster here. I'm usually able to get quite a lot of info from other posts on the site but i can't find a solution for this particular problem. Using xslt, I'm currently able to show a sub total of each client invoice then the total of those invoices by adding another variable of $grandtotal to my below xslt template and adding the $sum to it in each iteration of the loop.

What I now need to do is to find the top 5 highest totaling invoices.

This is a shortened version of my XML:

<bits>
    <client type="Commercial">
    <clientid>1</clientid>
            <inv>
            <invno>1</invno>
                <product>
                    <productid>321</productid>
                    <productprice>99.00</productprice>
                    <totalqty>2</totalqty>
                </product>
                <product>
                    <productid>333</productid>
                    <productprice>299.00</productprice>
                    <totalqty>1</totalqty>
            </product>
        </inv>
            <inv>
            <invno>2</invno>
                <product>
                    <productid>321</productid>
                    <productprice>99.00</productprice>
                    <totalqty>2</totalqty>
                </product>
                <product>
                    <productid>333</productid>
                    <productprice>299.00</productprice>
                    <totalqty>2</totalqty>
            </product>
        </inv>
    </client>
    <client type="Government">
        <clientid>2</clientid>
        <inv>
            <invno>3</invno>
            <product>
                <productid>399</productid>
                <productprice>1469.00</productprice>
                <totalqty>1</totalqty>
                </product>
            <product>
                <productid>354</productid>
                <productprice>15.00</productprice>
                <totalqty>1</totalqty>
            </product>
                <product>
                <productid>311</productid>
                <productprice>58.00</productprice>
                <totalqty>1</totalqty>
            </product>
                <product>
                    <productid>341</productid>
                    <productprice>199.00</productprice>
                    <totalqty>1</totalqty>
                </product>
        </inv>
    </client>
</bits>

I have used the following code to sum the invoice total for each client:

<xsl:for-each select="//client">
    <xsl:call-template name="sum">
        <xsl:with-param name="nodes" select="inv/product"/>
    </xsl:call-template>
</xsl:for-each>

<xsl:template name="sum">
<xsl:param name="nodes" />
<xsl:param name="sum" select="0" />
<xsl:variable name="current" select="$nodes[1]" />
<xsl:if test="$current">
  <xsl:call-template name="sum">
    <xsl:with-param name="nodes" select="$nodes[position() &gt; 1]" />
    <xsl:with-param name="sum" select="$sum + $current/totalqty * $current/productprice" />
  </xsl:call-template>
</xsl:if>
<xsl:if test="not($current)">
  <xsl:value-of select="$sum" />
</xsl:if>

What I'd like to do is reuse this code to also show the 5 highest summing invoice and their corresponding <clientid> and type eg:

Top 5:

1. Clientid: 2, Invoice no: 3, Invoice total: $1741, Type: Government
2. Clientid: 1, Invoice no: 2, Invoice total: $796, Type: Commercial
3. Clientid: 1, Invoice no: 1, Invoice total: $497, Type: Commercial

In the past i have used a for loop <xsl:for-each select=...> <xsl:sort select="Total" data-type="number" order="descending"/> ...<xsl:if test="position()&lt;6"> to show top 5 but this is looking at a stored value. I will need another solution.

I need some tips at this point as I'm still very new to markup!

Answer 1

This XSLT 1.0 style-sheet...

<xsl:stylesheet version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:exsl="http://exslt.org/common"
  exclude-result-prefixes="xsl exsl">
<xsl:output method="html" indent="yes" />
<xsl:strip-space elements="*" />

<xsl:template match="/*">
  <table>
    <th><td>Client id</td><td>Invoice no</td><td>Invoice total</td>
        <td>Type</td></th>
    <xsl:variable name="rows">
      <xsl:apply-templates select="client/inv" />
    </xsl:variable>
    <xsl:for-each select="exsl:node-set($rows)/tr">
      <xsl:sort select="td[4]" data-type="number" order="descending" />
      <xsl:variable name="rank" select="position()" />
      <xsl:copy-of select="self::node()[$rank &lt; 6]" />
    </xsl:for-each>
  </table>
</xsl:template>

<xsl:template match="inv">
  <tr>
    <td><xsl:value-of select="../clientid" /></td>
    <td><xsl:value-of select="invno" /></td>
    <xsl:variable name="gross-prices">
      <xsl:for-each select="product">
        <t><xsl:value-of select="productprice * totalqty" /></t> 
      </xsl:for-each>  
    </xsl:variable>  
    <td><xsl:value-of select="sum( exsl:node-set($gross-prices)/t)" /></td>
    <td><xsl:value-of select="../@type" /></td>
  </tr>
</xsl:template>

</xsl:stylesheet>

...when applied to this input...

<bits>
    <client type="Commercial">
    <clientid>1</clientid>
            <inv>
            <invno>1</invno>
                <product>
                    <productid>321</productid>
                    <productprice>99.00</productprice>
                    <totalqty>2</totalqty>
                </product>
                <product>
                    <productid>333</productid>
                    <productprice>299.00</productprice>
                    <totalqty>1</totalqty>
            </product>
        </inv>
            <inv>
            <invno>2</invno>
                <product>
                    <productid>321</productid>
                    <productprice>99.00</productprice>
                    <totalqty>2</totalqty>
                </product>
                <product>
                    <productid>333</productid>
                    <productprice>299.00</productprice>
                    <totalqty>2</totalqty>
            </product>
        </inv>
    </client>
    <client type="Government">
        <clientid>2</clientid>
        <inv>
            <invno>3</invno>
            <product>
                <productid>399</productid>
                <productprice>1469.00</productprice>
                <totalqty>1</totalqty>
                </product>
            <product>
                <productid>354</productid>
                <productprice>15.00</productprice>
                <totalqty>1</totalqty>
            </product>
                <product>
                <productid>311</productid>
                <productprice>58.00</productprice>
                <totalqty>1</totalqty>
            </product>
                <product>
                    <productid>341</productid>
                    <productprice>199.00</productprice>
                    <totalqty>1</totalqty>
                </product>
        </inv>
    </client>
</bits>

...yields...

<table>
  <th>
    <td>Client id</td>
    <td>Invoice no</td>
    <td>Invoice total</td>
    <td>Type</td>
  </th>
  <tr>
    <td>2</td>
    <td>3</td>
    <td>1741</td>
    <td>Government</td>
  </tr>
  <tr>
    <td>1</td>
    <td>2</td>
    <td>796</td>
    <td>Commercial</td>
  </tr>
  <tr>
    <td>1</td>
    <td>1</td>
    <td>497</td>
    <td>Commercial</td>
  </tr>
</table>

Notes

As long as we have access to node-set(), we don't need to fold or divide-and-conquer to calculate sums. We can simply use the native sum() function.