Summating/grouping

I know, I know... This sort of thing has been asked many times. However, I
am not clear/understand why I do not have any results appearing.

using this xml

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="c:\temp\a.xsl"?>
<Invoice>
	<InvoiceLine Line="1">
		<Charge Type="Tax">
			<TaxRate Code="E">0.0</TaxRate>
			<Value>0.00</Value>
		</Charge>
	</InvoiceLine>
	<InvoiceLine Line="2">
		<Charge Type="Tax">
			<TaxRate Code="S">17.5</TaxRate>
			<Value>12.50</Value>
		</Charge>
	</InvoiceLine>
	<InvoiceLine Line="3">
		<Charge Type="Tax">
			<TaxRate Code="E">0.0</TaxRate>
			<Value>0.00</Value>
		</Charge>
	</InvoiceLine>
	<InvoiceLine Line="4">
		<Charge Type="Tax">
			<TaxRate Code="S">17.5</TaxRate>
			<Value>15.00</Value>
		</Charge>
	</InvoiceLine>
	<InvoiceLine Line="5">
		<Charge Type="Tax">
			<TaxRate Code="Z">0.0</TaxRate>
			<Value>0.00</Value>
		</Charge>
	</InvoiceLine>
</Invoice>


I would like to achieve...

<TaxSummary>
    <Tax Code="S">
        <Rate>17.5</Rate>
        <LinesAtRate>2</LinesAtRate>
        <Value>27.50</Value>
    </Tax>
    <Tax Code="E">
        <Rate>0.0</Rate>
        <LinesAtRate>2</LinesAtRate>
        <Value>0.0</Value>
    </Tax>
    <Tax Code="Z">
        <Rate>17.5</Rate>
        <LinesAtRate>1</LinesAtRate>
        <Value>0.0</Value>
    </Tax>
</TaxSummary>


I try using this XSL

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
	<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
	<!--	I am hoping that this builds up a list of all the items by Tax rate
code -->
	<xsl:key name="TAX" match="/Invoice/InvoiceLine/Charge[@Type =
'Tax']/TaxRate" use="@Code"/>
	<xsl:template match="/">
		<TaxSummary>
			<!--	I am hoping that this will return the first element of each of the
Tax codes, i.e. 'S', 'E', 'Z' -->
			<xsl:for-each select="/Invoice/InvoiceLine/Charge[@Type =
'Tax']/TaxRate/@Code[generate-id(.)=generate-id(key('TAX', @Code)[1])]">
				<!-- this should be the TaxRate Code -->
				<xsl:variable name="CODE" select="."/>
				<Tax Code="{$CODE}">
					<Rate>
						<xsl:value-of select="TaxRate"/>
					</Rate>
					<LinesAtRate>
						<xsl:value-of select="count(/Invoice/InvoiceLine/Charge[@Type =
'Tax']/TaxRate[@Code = $CODE])"/>
					</LinesAtRate>
					<Value>
						<xsl:value-of select="sum(/Invoice/InvoiceLine/Charge[@Type =
'Tax']/TaxRate[@Code = $CODE]/../Value)"/>
					</Value>
				</Tax>
			</xsl:for-each>
		</TaxSummary>
	</xsl:template>
</xsl:stylesheet>



Many thanks

Rob



 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list