my $neid = 2329;
my $query = "SELECT Root.NEID, State.NEID FROM Root, State WHERE Root.NEID = ?";
my $sth = $dbh->prepare($query) or die $dbh->errstr();
$sth->execute($neid);

my ($root,$state) = $sth->fetchrow_array();

if(not defined $state){
    $dbh->do("INSERT INTO State(NEID) VALUES(?)",undef,$neid) or die $dbh->errstr();
}

if(not defined $root){
    $dbh->do("INSERT INTO Root(NEID) VALUES(?)",undef,$neid) or die $dbh->errstr();
}