XSLT: Check if string contains any value from another group of nodes - xslt

Question

I have this XML:
<table tableName="Groups">
<item table="Groups">
<column columnName="GroupID">GROUP1</column>
<column columnName="GroupID">GROUP2</column>
</item>
</table>
<table tableName="Products">
<item table="Products">
<column columnName="ProductID">1</column>
<column columnName="ProductName">Product A</column>
<column columnName="Groups">"GROUP1","GROUP2"</column>
</item>
<item table="EcomProducts">
<column columnName="ProductID">2</column>
<column columnName="ProductName">Product B</column>
<column columnName="Groups">"GROUP3","GROUP4"</column>
</item>
<item table="EcomProducts">
<column columnName="ProductID">3</column>
<column columnName="ProductName">Product C</column>
<column columnName="Groups">"GROUP1","GROUP3"</column>
</item>
</table>
I'm trying to filter out products that has any groups that are present in the Groups-table.
I would like to end up with this.
<products>
<product>
<name>Product A</name>
<groups>"GROUP1","GROUP2"</groups>
</product>
<product>
<name>Product C</name>
<groups>"GROUP1","GROUP3"</groups>
</product>
</products>
So far I have this XSLT, but as I'm pretty new to XSLT, I have no idea how to make that test-statement more dynamic:
<products>
<xsl:for-each select="table[#tableName='Products']/item">
<xsl:if test="contains(column[#columnName = 'Groups'] = 'GROUP1' and contains(column[#columnName = 'Groups'] = 'GROUP2'">
<product>
<name><xsl:value-of select="column[#columnName = 'ProductName']"/></name>
<groups><xsl:value-of select="column[#columnName = 'Groups']"/></groups>
</product>
</xsl:if>
</xsl:for-each>
</products>

Answer 1

Try it this way:
XSLT 1.0
<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"/>
<xsl:template match="/root">
<xsl:variable name="group-ids" select="table[#tableName='Groups']/item/column[#columnName='GroupID']" />
<products>
<xsl:for-each select="table[#tableName='Products']/item">
<xsl:if test="$group-ids[contains(current()/column[#columnName='Groups'], concat('"', ., '"'))]">
<product>
<name>
<xsl:value-of select="column[#columnName='ProductName']"/>
</name>
<groups>
<xsl:value-of select="column[#columnName='Groups']"/>
</groups>
</product>
</xsl:if>
</xsl:for-each>
</products>
</xsl:template>
</xsl:stylesheet>
Demo: https://xsltfiddle.liberty-development.net/jxNakB6
However, if your processor happens to support the EXSLT str:tokenize() extension function, you could do something a bit simpler:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:str="http://exslt.org/strings"
extension-element-prefixes="exsl str">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:key name="grp-id" match="table[#tableName='Groups']/item/column[#columnName='GroupID']" use="concat('"', ., '"')" />
<xsl:template match="/root">
<products>
<xsl:for-each select="table[#tableName='Products']/item[key('grp-id', str:tokenize(column[#columnName='Groups'], ','))]">
<product>
<name>
<xsl:value-of select="column[#columnName='ProductName']"/>
</name>
<groups>
<xsl:value-of select="column[#columnName='Groups']"/>
</groups>
</product>
</xsl:for-each>
</products>
</xsl:template>
</xsl:stylesheet>

Answer 2

XSLT 1.0 solution, using keys:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:key name="kContainsGroup" match="item[not(#table='Groups')]"
use="boolean(
/*/table[#tableName='Groups']/item/column
[contains(current()/column[#columnName='Groups'],
concat('"', ., '"'))]
)"/>
<xsl:template match="/">
<products>
<xsl:apply-templates select="key('kContainsGroup', 'true')"/>
</products>
</xsl:template>
<xsl:template match="item">
<product>
<name><xsl:value-of select="column[#columnName='ProductName']"/></name>
<groups><xsl:value-of select="column[#columnName='Groups']"/></groups>
</product>
</xsl:template>
</xsl:stylesheet>
When this transformation is applied on the provided XML (fragment, made a well-formed XML document by enclosing it within a single top element <tables>):
<tables>
<table tableName="Groups">
<item table="Groups">
<column columnName="GroupID">GROUP1</column>
<column columnName="GroupID">GROUP2</column>
</item>
</table>
<table tableName="Products">
<item table="Products">
<column columnName="ProductID">1</column>
<column columnName="ProductName">Product A</column>
<column columnName="Groups">"GROUP1","GROUP2"</column>
</item>
<item table="EcomProducts">
<column columnName="ProductID">2</column>
<column columnName="ProductName">Product B</column>
<column columnName="Groups">"GROUP3","GROUP4"</column>
</item>
<item table="EcomProducts">
<column columnName="ProductID">3</column>
<column columnName="ProductName">Product C</column>
<column columnName="Groups">"GROUP1","GROUP3"</column>
</item>
</table>
</tables>
the wanted, correct result is produced:
<products>
<product>
<name>Product A</name>
<groups>"GROUP1","GROUP2"</groups>
</product>
<product>
<name>Product C</name>
<groups>"GROUP1","GROUP3"</groups>
</product>
</products>
Do note:
No XSLT conditional instruction (such as <xsl:if>) has been used.
No <xsl:for-each> instruction has been used
The solution is implemented in almost pure "push-style"