| (: XQuery Join Query :) | |
| (: Count all the weather sensor readings on 1976-07-04. :) | |
| count( | |
| let $sensor_collection := "/tmp/1.0_partition_ghcnd_all_xml/sensors" | |
| for $r in collection($sensor_collection)/dataCollection/data | |
| let $date := xs:date(fn:substring(xs:string(fn:data($r/date)), 0, 11)) | |
| where $date eq xs:date("1976-07-04") | |
| return $r | |
| ) |