XQuery Query counting

Question

I'm learning XQuery for the first time and I'm running into a spot of trouble with a particular query.

Find the names of the Makers who produce at least two PC's with speed of at least 2.00.

I've gotten the Speed<=2.00 part of the query down pat, but I can't quite figure out how to group this by number of occurrences.

Attempt: (outputs nothing)

let $doc := doc("PC.xml")
for $x in $doc/Products/Maker/PC
where $x/Speed>=2.00 and count($x)>=2
return $x/../@name

PC.xml:

<Products>
    <Maker name = "A">
        <PC model = "1001" price = "2114">
            <Speed>2.66</Speed>
            <RAM>1024</RAM>
            <HardDisk>250</HardDisk>
        </PC>
        <PC model = "1002" price = "995">
            <Speed>2.10</Speed>
            <RAM>512</RAM>
            <HardDisk>250</HardDisk>
        </PC>
        <Laptop model = "2004" price = "1150">
            <Speed>2.00</Speed>
            <RAM>512</RAM>
            <HardDisk>60</HardDisk>
            <Screen>13.3</Screen>
        </Laptop>
        <Laptop model = "2005" price = "2500">
            <Speed>2.16</Speed>
            <RAM>1024</RAM>
            <HardDisk>120</HardDisk>
            <Screen>17.0</Screen>
        </Laptop>
    </Maker>
    <Maker name = "E">
        <PC model = "1011" price = "959">
            <Speed>1.86</Speed>
            <RAM>2048</RAM>
            <HardDisk>160</HardDisk>
        </PC>
        <PC model = "1012" price = "649">
            <Speed>2.80</Speed>
            <RAM>1024</RAM>
            <HardDisk>160</HardDisk>
        </PC>
        <Laptop model = "2001" price = "3673">
            <Speed>2.00</Speed>
            <RAM>2048</RAM>
            <HardDisk>240</HardDisk>
            <Screen>20.1</Screen>
        </Laptop>
        <Printer model = "3002" price = "239">
            <Color>false</Color>
            <Type>laser</Type>
        </Printer>
    </Maker>
    <Maker name = "H">
        <Printer model = "3006" price = "100">
            <Color>true</Color>
            <Type>ink--jet</Type>
        </Printer>
        <Printer model = "3007" price = "200">
            <Color>true</Color>
            <Type>laser</Type>
        </Printer>
    </Maker>
</Products>

Unknown Unknown · Accepted Answer · 2012-08-03T01:13:06

egads, I've figured it out!

let $doc := doc("PC.xml")/Products
for $maker in $doc//Maker
where count($maker/PC[Speed >= 3.00]) >= 2
return data($maker/@name)

XQuery Query counting

2 Answers