my $q1 = $dbh->prepare("sql statement");
my $q2 = $dbh->prepare("sql statement 2 with ?");

$q1->execute();

while($data = $q1->fetchrow_hashref()){
   $q2->execute($data->{field});
   while($more_data = $q2->fetrow_hashref()){
      # code here
   }
}

##</code><code>##

my $sth = $dbh->prepare("select * from table where field = :nam");
$sth->bind_param(':nam', $value);
$sth->execute();