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   regarding copyright ownership.  The ASF licenses this file
   to you under the Apache License, Version 2.0 (the
   "License"); you may not use this file except in compliance
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   "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   KIND, either express or implied.  See the License for the
   specific language governing permissions and limitations
   under the License. :)

(: XQuery Join Aggregate Query :)
(: Find the lowest recorded temperature (TMIN) in the United States for     :)
(: 2001.                                                                      :)
    let $station_collection := "ghcnd_quarter_1|ghcnd_quarter_2|ghcnd_quarter_3|ghcnd_quarter_4"
    for $s in collection($station_collection)/stationCollection/station
    
    let $sensor_collection := "ghcnd_quarter_1|ghcnd_quarter_2|ghcnd_quarter_3|ghcnd_quarter_4"
    for $r in collection($sensor_collection)/dataCollection/data
    
    where $s/id eq $r/station
        and (some $x in $s/locationLabels satisfies ($x/type eq "CNTRY" and $x/id eq "FIPS:US"))
        and $r/dataType eq "TMIN" 
        and fn:year-from-dateTime(xs:dateTime(fn:data($r/date))) eq 2001
    return $r/value