XML/XQuery/Aggregate

Aggregating values

File: Data.xml
<employees>
  <employee name="James" salary="1234" yearServed="1" location="North"/>
  <employee name="Joe"   salary="3211" yearServed="2" location="South"/>
  <employee name="Jod"   salary="3422" yearServed="3" location="North"/>
  <employee name="Jason" salary="1321" yearServed="4" location="East"/>
  <employee name="Jack"  salary="2324" yearServed="3" location="North"/>
  <employee name="Jeep"  salary="4321" yearServed="2" location="East"/>
  <employee name="Jane"  salary="2344" yearServed="1" location="South"/>
</employees>
File: Query.xquery
for $d in distinct-values(doc("Data.xml")//employee/@location)
let $employees := doc("Data.xml")//employee[@location= $d]
order by $d
return <department name="{$d}" total="{sum($employees/@yearServed)}"/>
Output:
<?xml version="1.0" encoding="UTF-8"?>
<department total="6" name="East"/>
<department total="7" name="North"/>
<department total="3" name="South"/>

Aggregation

File: Data.xml
<employees>
  <employee name="James" salary="1234" yearServed="1" location="North"/>
  <employee name="Joe"   salary="3211" yearServed="2" location="South"/>
  <employee name="Jod"   salary="3422" yearServed="3" location="North"/>
  <employee name="Jason" salary="1321" yearServed="4" location="East"/>
  <employee name="Jack"  salary="2324" yearServed="3" location="North"/>
  <employee name="Jeep"  salary="4321" yearServed="2" location="East"/>
  <employee name="Jane"  salary="2344" yearServed="1" location="South"/>
</employees>
File: Query.xquery
for $d in distinct-values(doc("Data.xml")//employee/@location)
let $employees := doc("Data.xml")//employee[@location = $d]
order by $d
return <department code="{$d}"
                   numemployees="{count($employees)}"
                   distinct="{count(distinct-values($employees/@yearServed))}"
                   total="{sum($employees/@yearServed)}"/>
Output:
<?xml version="1.0" encoding="UTF-8"?>
<department total="6" code="East" distinct="2" numemployees="2"/>
<department total="7" code="North" distinct="2" numemployees="3"/>
<department total="3" code="South" distinct="2" numemployees="2"/>

Aggregation on multiple values

File: Data.xml
<employees>
  <employee name="James" salary="1234" yearServed="1" location="North"/>
  <employee name="Joe"   salary="3211" yearServed="2" location="South"/>
  <employee name="Jod"   salary="3422" yearServed="3" location="North"/>
  <employee name="Jason" salary="1321" yearServed="4" location="East"/>
  <employee name="Jack"  salary="2324" yearServed="3" location="North"/>
  <employee name="Jeep"  salary="4321" yearServed="2" location="East"/>
  <employee name="Jane"  salary="2344" yearServed="1" location="South"/>
</employees>
File: Query.xquery
let $allemployees := doc("Data.xml")//employee
for $d in distinct-values($allemployees/@salary)
for $n in distinct-values($allemployees[@salary = $d]/@yearServed)
let $employees := $allemployees[@salary = $d and @yearServed = $n]
order by $d, $n
return <group salary="{$d}" 
              yearServed="{$n}"
              numemployees="{count($employees)}"
              total="{sum($employees/@yearServed)}"/>
Output:
<?xml version="1.0" encoding="UTF-8"?>
<group total="1" yearServed="1" salary="1234" numemployees="1"/>
<group total="4" yearServed="4" salary="1321" numemployees="1"/>
<group total="3" yearServed="3" salary="2324" numemployees="1"/>
<group total="1" yearServed="1" salary="2344" numemployees="1"/>
<group total="2" yearServed="2" salary="3211" numemployees="1"/>
<group total="3" yearServed="3" salary="3422" numemployees="1"/>
<group total="2" yearServed="2" salary="4321" numemployees="1"/>

Constraining and sorting on aggregated values

File: Data.xml
<inventory id="inv0001" date="2008-12-19" loc="USA">
  <car model="A" num="0001" quantity="1" color="navy"/>
  <car model="B" num="0002" quantity="1" color="red"/>
  <car model="B" num="0003" quantity="2" color="red"/>
  <car model="C" num="0004" quantity="1" color="white"/>
  <car model="C" num="0004" quantity="1" color="gray"/>
  <car model="A" num="0001" quantity="1" color="black"/>
</inventory>

File: Query.xquery
let $allcars := doc("Data.xml")//car
for $d in distinct-values($allcars/@model)
for $n in distinct-values($allcars/@num)
let $cars := $allcars[@model = $d and @num = $n]
where sum($cars/@quantity) > 1
order by count($cars)
return if (exists($cars))
       then <group model="{$d}" num="{$n}" numcars="{count($cars)}"
                   totQuant="{sum($cars/@quantity)}"/>
       else ()
Output:
<?xml version="1.0" encoding="UTF-8"?>
<group totQuant="2" num="0003" model="B" numcars="1"/>
<group totQuant="2" num="0001" model="A" numcars="2"/>
<group totQuant="2" num="0004" model="C" numcars="2"/>