Fetching common elements using XQuery

Question

I am stuck with a problem using XQuery to return common elements based on a tag. I am trying to write a XQ function which returns the common elements. For example I have an XML as: $schoolA

<schoolA>
    <name>ABC</name>
    <students>1000</students>
    <classes>25</classes>
</schoolA>
<schoolA>
    <name>DEF</name>
    <students>1200</students>
    <classes>20</classes>
</schoolA>
<schoolA>
    <name>GHY</name>
    <students>900</students>
    <classes>30</classes>
</schoolA>

The other one as: $schoolB

<schoolB>
    <name>ABC</name>
    <students>1000</students>
    <classes>25</classes>
</schoolB>
<schoolB>
    <name>DEF</name>
    <students>1200</students>
    <classes>20</classes>
</schoolB>
<schoolB>
    <name>XYZ</name>
    <students>1100</students>
    <classes>30</classes>
</schoolB>

The function should return: $commonSchool

<schoolA>
    <name>ABC</name>
    <students>1000</students>
    <classes>25</classes>
</schoolA>
<schoolA>
    <name>DEF</name>
    <students>1200</students>
    <classes>20</classes>
</schoolA>

The matching factor is the name. I am trying to write a nested for loop, but stuck appending the element to a variable. Any clues on how to do it would be great!

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Chondrops Chondrops · Accepted Answer · 2016-09-05T14:42:59

This XQuery function matches two sequences of elements based on the value of the <name> element. Assumption for simplicity is that you have wrapped your two sets of School elements in a wrapper called <schools>.

This works with XQuery 1.0.

declare namespace _="http://local/funcs";

declare function _:munge($schoolA as element()*, $schoolB as element()*) {
    $schoolA[name=$schoolB/name]
};

_:munge(schools/schoolA, schools/schoolB)

Fetching common elements using XQuery

1 Answers