my $sql =<<'EOFSQL';
SELECT 
LOWER(field_one), field_two, UPPER(field_three)
FROM sample_table (NOLOCK)
WHERE
field_one = ?
EOFSQL

my $sth = $dbh->prepare($sql) or die;

my ($field_one, $field_two, $field_three);

for my $test_value (@test_values) {
  $sth->bind_param(1, $test_value);
  $sth->execute;
  $sth->bind_columns(\$field_one, \$field_two, \$field_three);
  while ($sth->fetch) {
    print join "-", ($field_one, $field_two, $field_three);
  }
}