XSLT logic to add a sequence for the combination of elements with same dates and ID field - xslt

Question

I am struggling to create logic for transformation.
Logic: "Seq" A sequential number used to make a unique key when the ID and Date fields are equal.
<root>
<Record>
<ID>11</ID>
<date>2020-03-11-07:00</date>
<quantity>10</quantity>
</Record>
<Record>
<ID>13</ID>
<date>2020-03-12-07:00</date>
<quantity>20</quantity>
</Record>
<Record>
<ID>15</ID>
<date>2020-03-13-07:00</date>
<quantity>40</quantity>
</Record>
<Record>
<ID>11</ID>
<date>2020-03-11-07:00</date>
<quantity>5</quantity>
</Record>
<Record>
<ID>13</ID>
<date>2020-03-17-07:00</date>
<quantity>100</quantity>
</Record>
</root>
to, Output
ID,seq,Date,quantity
11,1,2020-03-11-07:00,10
11,2,2020-03-11-07:00,5
13,1,2020-03-12-07:00,20
15,1,2020-03-13-07:00,40
13,1,2020-03-17-07:00,100

Answer 1

In XSLT 3 it is a simple grouping problem with a composite key:
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="#all"
version="3.0">
<xsl:output method="text" />
<xsl:template match="root">
<xsl:text>ID,seq,Date,quantity
</xsl:text>
<xsl:for-each-group select="Record" composite="yes" group-by="ID, date">
<xsl:apply-templates select="current-group()"/>
</xsl:for-each-group>
</xsl:template>
<xsl:template match="Record">
<xsl:value-of select="ID, position(), date, quantity" separator=","/>
<xsl:text>
</xsl:text>
</xsl:template>
</xsl:stylesheet>
https://xsltfiddle.liberty-development.net/93dFepy
XSLT 3 can be used with Saxon 9.8 and later or AltovaXML 2017 R3 or later.