BaseX xQuery for exporting a database of TCX moves to a csv file

tcx_to_csv_basex.xqy

(:
Outputs all Trackpoints in the BaseX database 'moves' in CSV format with columns in following order
ID - Activity identifier
SPORT - Sport (Running|Biking|Other)
TIMESTAMP - Timestamp as UNIX epoch
LAT - Latitude as degrees
LONG - Longitude as degrees
HR - Heart rate as BPM (integer)
ALT - Altitude as float
CAD - Cadence as integer
:)
declare function local:get-val($el as node()*) {
	if (empty($el)) then (
	   <empty></empty>
	   ) else (
	   $el
	   )
};
for $a in db:open('moves')//*:Activity
    for $tp in $a/*/*/*:Trackpoint
    	let $ts := convert:dateTime-to-integer(xs:dateTime($tp/*:Time))
	let $lat := local:get-val($tp/*/*:LatitudeDegrees)
	let $long := local:get-val($tp/*/*:LongitudeDegrees)
	let $hr := local:get-val($tp/*:HeartRateBpm/*:Value)
	let $alt := local:get-val($tp/*:AltitudeMeters)
	let $cad := local:get-val($tp/*:Cadence)
	return string-join(($a/*:Id,$a/@Sport,$ts,$lat,$long,$hr,$alt,$cad), ",")