| (: Licensed to the Apache Software Foundation (ASF) under one |
| or more contributor license agreements. See the NOTICE file |
| distributed with this work for additional information |
| 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 |
| with the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, |
| software distributed under the License is distributed on an |
| "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 Self Join Query :) |
| (: Self join with all stations finding the difference in min and max :) |
| (: temperature and get the average. :) |
| fn:avg( |
| let $sensor_collection_min := "ghcnd" |
| for $r_min in collection($sensor_collection_min)/dataCollection/data |
| |
| let $sensor_collection_max := "ghcnd" |
| for $r_max in collection($sensor_collection_max)/dataCollection/data |
| |
| where $r_min/station eq $r_max/station |
| and $r_min/date eq $r_max/date |
| and $r_min/dataType eq "TMIN" |
| and $r_max/dataType eq "TMAX" |
| return $r_max/value - $r_min/value |
| ) div 10 |