[Koha] Patrons with no issues SQL report

Dear all Koha has a built in report "Patrons who haven't checked out <http://192.168.1.122:81/cgi-bin/koha/reports/borrowers_out.pl>" or Patrons with no Checkouts. It looks as if it should do what I need, but whatever date I enter, I get no results. I cannot see the SQL used to generate the report so I can't tell why I get nothing. Can anyone send me the SQL for this - patrons with no checkout history since specified date? Many thanks Agnes -- Agnes Rivers-Moore Assistant Librarian Hanover Public Library