XML and XSL connection

Answer 1

See my XSLT 1.0 and 2.0 solution below. The problem in your code is:

<xsl:value-of select="description [@courseCode = text()]"/>

This means that you are looking for the element description whose attribute courseCode is the same as its text value. What I do is to save the course code in a variable and check for course elements whose attribute is the same as this variable.

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">
  <xsl:output indent="yes" />

  <xsl:template match="/">
    <ol>
      <xsl:for-each select="/school/student">
        <xsl:sort data-type="text" order="ascending" select="name" />
        <li>
          <xsl:value-of select="name" />
          <ol type="a">
            <xsl:for-each select="takes">
              <xsl:sort data-type="text" select="." order="ascending" />
              <li>
                <xsl:variable name="coursecode" select="." />
                <xsl:value-of select="concat('(',.,') ')" />
                <xsl:for-each select="/school/course[@courseCode = $coursecode]">
                  <xsl:value-of select="description" />
                </xsl:for-each>

              </li>
            </xsl:for-each>
          </ol>
        </li>
      </xsl:for-each>
    </ol>
  </xsl:template>
</xsl:stylesheet>