I have following xml data

<?xml version="1.0" encoding="UTF-8"?>
<datas>
<data>
<item id="9191" title="First">
<datafield>
<label>item_type_code</label>
<entry>PA</entry>
</datafield>
<datafield>
<label>item_type_description</label>
<entry>PA</entry>
</datafield>
</item>
<item id="9695">
<datafield>
<label>item_type_code</label>
<entry>OE</entry>
</datafield>
<datafield>
<label>item_type_description</label>
<entry>OEE</entry>
</datafield>

</item>
</data>
<data>
<item id="9291" title="Second">
<datafield>
<label>item_type_code</label>
<entry>PA</entry>
</datafield>
<datafield>
<label>item_type_description</label>
<entry>PAA</entry>
</datafield>
</item>
<item id="1086">
<datafield>
<label>item_type_code</label>
<entry>PP</entry>
</datafield>
<datafield>
<label>item_type_description</label>
<entry>PPA</entry>
</datafield>

</item>
</data>
<data>
<item id="9993" title="Four">
<datafield>
<label>item_type_code</label>
<entry>PA</entry>
</datafield>
<datafield>
<label>item_type_description</label>
<entry>PAA</entry>
</datafield>
</item>
<item id="9983" title="Fifty">
<datafield>
<label>item_type_code</label>
<entry>PA</entry>
</datafield>
<datafield>
<label>item_type_description</label>
<entry>PAA</entry>
</datafield>
</item>

<item id="8987">
<datafield>
<label>item_type_code</label>
<entry>OE</entry>
</datafield>
<datafield>
<label>item_type_description</label>
<entry>OEE</entry>
</datafield>

</item>
</data>
<data>
<item id="9993" title="Four">
<datafield>
<label>item_type_code</label>
<entry>PA</entry>
</datafield>
<datafield>
<label>item_type_description</label>
<entry>PAA</entry>
</datafield>
</item>
<item id="9987" title="Six">
<datafield>
<label>item_type_code</label>
<entry>PA</entry>
</datafield>
<datafield>
<label>item_type_description</label>
<entry>PAA</entry>
</datafield>
</item>
<item id="9687">
<datafield>
<label>item_type_code</label>
<entry>OE</entry>
</datafield>
<datafield>
<label>item_type_description</label>
<entry>OEE</entry>
</datafield>
</item>
</data>
<data>
<item id="9168" title="Sevent">
<datafield>
<label>item_type_code</label>
<entry>PA</entry>
</datafield>
<datafield>
<label>item_type_description</label>
<entry>PAA</entry>
</datafield>
</item>
<item id="9087" title="Ten">
<datafield>
<label>item_type_code</label>
<entry>PA</entry>
</datafield>
<datafield>
<label>item_type_description</label>
<entry>PAA</entry>
</datafield>
</item>
<item id="9487">
<datafield>
<label>item_type_code</label>
<entry>OE</entry>
</datafield>
<datafield>
<label>item_type_description</label>
<entry>OEE</entry>
</datafield>
</item>
</data>
</datas>



And my xsl as following

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xml:space="default">

<xsl:template match="/">
<xsl:apply-templates select="//item" mode="passage"/>
</xsl:template>
<xsl:template match="item" mode="passage">
<xsl:if test="descendant::datafield/entry[preceding-sibling::node()[text()='item_type_code']]/text()='OE'">

1. Found OE item

<xsl:for-each select="preceding-sibling::item[@title !='']">
2. Found a Passage item that relate to OE item.
<xsl:variable name="pass_id" select="@id"/>

<xsl:if test="not(preceding-sibling::item/@id = $pass_id)">
pa_ident= <xsl:value-of select="@id"/><br></br>
  3.Don't print duplicate passage
</xsl:if>

</xsl:for-each>

</xsl:if>

</xsl:template>

</xsl:stylesheet>


I want the Out put as :
pa_ident= 9191
pa_ident= 9993
pa_ident= 9983
pa_ident= 9987
pa_ident= 9160
pa_ident= 9087

but I can’t filtering the duplicated item out (pa_ident= 9993).
Here's what I did:
step1:Found OE item
step2: Found a PA item that relate to OE item.
step3: filter out the duplicated PA item

(I can't get step3 work correctly)
Thanks you in advance.
Fanyin

One way I can think of is to use a different search path.
Please correct me if I'm wrong.

So step by step:
Find a matching datafield:
datas/data/item/datafield[entry='OE' and label='item_type_code']

Find data:
datas/data/item/datafield[entry='OE' and label='item_type_code']/../..

Find PA items in the same data as an OE item:
datas/data/item/datafield[entry='OE' and label='item_type_code']/../..item/datafield[entry='PA' and label='item_type_code']/..

so find them all and sort them by id.
<xsl:for-each select="datas/data/item/datafield[entry='OE' and label='item_type_code']/../..item/datafield[entry='PA' and label='item_type_code']/..">
<xsl:sort select="@id">
</xsl:for-each>

should be a lot easier to check if there is a duplicate this way. I hope this helps!:)

Thank you very much for letting me learn the solution. Fanyin