Using sum() to sum up values with nested foreach() - xslt

Question

I need help in properly specifying the input parameter for sum(). I encountered sum()'s output to concatenate the values instead of summing up.
My goal is: To sum values of Column6 when Column2 is "invoice"
In the example below, I have 2000 and 1000 for Column6 whose Column is "invoice".
I'm expecting it to display 3000 for <TotalAmount>
<Root>
<DataArea>
<Row>... </Row>
<Row>... </Row>
<!-- and so on -->
<Row>
<Column1>29/03/19</Column1>
<Column2>cr note</Column2>
<Column3>092-213280101</Column3>
<Column4>1,474.98 </Column4>
<Column5>103.25 </Column5>
<Column6>2000 </Column6>
</Row>
<Row>
<Column1>29/03/19</Column1>
<Column2>invoice</Column2>
<Column3>092-213280101</Column3>
<Column4>1,474.98 </Column4>
<Column5>103.25 </Column5>
<Column6>2000 </Column6>
</Row>
<Row>
<Column1>11/06/19</Column1>
<Column2>invoice</Column2>
<Column3>123-123456789</Column3>
<Column4>100.50 </Column4>
<Column5>100.50 </Column5>
<Column6>1000</Column6>
</Row>
</DataArea>
</Root>
<xsl:for-each
select="Root/DataArea/Row">
<xsl:if ... >
<TransactionSummary>
<DebitSummary>
<TotalAmount>
<xsl:attribute name="currencyID"></xsl:attribute>
<xsl:for-each select="../Row">
<xsl:if test="(Column2 = 'invoice') and (position() > 9) ">
<xsl:value-of select="sum(../Column6)" />
</xsl:if>
</xsl:for-each>
</TotalAmount>
</DebitSummary>
</TransactionSummary>
</xsl:if>
</xsl:for-each>
I tried sum(Column6), didn't work. Output: 20001000
I tried sum(../Column6), didn't work. Output: 00
I tried sum(../Row/Column6), didn't work. Output: Cannot convert string "" to a double
I tried sum(Root/DataArea/Row/Column6), didn't work. Output: 00
I'd appreciate any help.
Thank you.

Answer 1

You don't need the inner xsl:for-each here, you can do it with a single xsl:value-of with the conditions in the select
<xsl:value-of select="sum(../Row[Column2 = 'invoice' and position() > 9]/Column6)" />
Or, in the context of your snippet....
<xsl:for-each select="Root/DataArea/Row">
<TransactionSummary>
<DebitSummary>
<TotalAmount currencyID="">
<xsl:value-of select="sum(../Row[Column2 = 'invoice' and position() > 9]/Column6)" />
</TotalAmount>
</DebitSummary>
</TransactionSummary>
</xsl:for-each>

Answer 2

It seems you want something like this:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:template match="/">
<TransactionSummary>
<DebitSummary>
<TotalAmount currencyID="someId">
<xsl:value-of select="sum(/*/*/Row[Column2 = 'invoice']/Column6)"/>
</TotalAmount>
</DebitSummary>
</TransactionSummary>
</xsl:template>
</xsl:stylesheet>
When this transformation is applied on the provided XML document:
<Root>
<DataArea>
<Row>... </Row>
<Row>... </Row>
<!-- and so on -->
<Row>
<Column1>29/03/19</Column1>
<Column2>cr note</Column2>
<Column3>092-213280101</Column3>
<Column4>1,474.98 </Column4>
<Column5>103.25 </Column5>
<Column6>2000 </Column6>
</Row>
<Row>
<Column1>29/03/19</Column1>
<Column2>invoice</Column2>
<Column3>092-213280101</Column3>
<Column4>1,474.98 </Column4>
<Column5>103.25 </Column5>
<Column6>2000 </Column6>
</Row>
<Row>
<Column1>11/06/19</Column1>
<Column2>invoice</Column2>
<Column3>123-123456789</Column3>
<Column4>100.50 </Column4>
<Column5>100.50 </Column5>
<Column6>1000</Column6>
</Row>
</DataArea>
</Root>
the wanted result is produced:
<TransactionSummary>
<DebitSummary>
<TotalAmount currencyID="someId">3000</TotalAmount>
</DebitSummary>
</TransactionSummary>