$DBversion = "3.21.00.XXX";

if ( CheckVersion($DBversion) ) {

    $sth = $dbh->prepare(q{

     SELECT s.itemnumber, i.itype, b.itemtype FROM

      ( SELECT DISTINCT itemnumber

        FROM statistics

        WHERE type="return" AND itemtype IS NULL ) s

      LEFT JOIN

      ( SELECT itemnumber,biblionumber, itype

        FROM items ) i

      ON (s.itemnumber=i.itemnumber)

      LEFT JOIN

      ( SELECT biblionumber, itemtype

        FROM biblioitems ) b

      ON (i.biblionumber=b.biblionumber)

    });

    $sth->execute();

    my $update_sth = $dbh->prepare(q{

        UPDATE statistics

        SET itemtype=?

        WHERE itemnumber=? AND itemtype IS NULL

    });

    my $ilevel_itypes = C4::Context->preference('item-level_itypes');

    while ( my ($itemnumber,$item_itype,$biblio_itype) = $sth->fetchrow_array ) {

        my $effective_itemtype = $ilevel_itypes

                                    ? $item_itype // $biblio_itype

                                    : $biblio_itype;

        warn "item-level_itypes set but no itype defined for item ($itemnumber)"

            if $ilevel_itypes and !defined $item_itype;

        $update_sth->execute( $effective_itemtype, $itemnumber );

    }

    print "Upgrade to $DBversion done (Bug 14598: itemtype is not set on statistics by C4::Circulation::AddReturn)\n";

    SetVersion($DBversion);

}