Mine

xquery version "1.0";
declare namespace sportsml="http://iptc.org/std/SportsML/2006-10-18/";
declare namespace xts="http://www.xmlteam.com";
declare namespace sportso="http://sportso.com/sportso";
declare namespace request="http://exist-db.org/xquery/request";
declare namespace xmldb="http://exist-db.org/xquery/xmldb";
declare namespace util="http://exist-db.org/xquery/util";

declare variable $league := request:get-parameter("league", "");
declare variable $team := request:get-parameter("team", "");
declare variable $league-doc := concat('/db/sportso/', $league, '/dynamic-resource-file/', $league, '.xml');

for $teams in doc($league-doc)/sports-content/statistic/group//team-metadata/@team-key=$team
return 
update delete $teams