my $sql = qq{
SELECT COUNT(*)
  FROM some_table
 WHERE some_column IN (} . join(',', (('?') x @values)) . ")";

##</code><code>##

my $sql = <<END_SQL;
SELECT COUNT(*)
  FROM some_table
 WHERE some_column = ?
END_SQL

my $sth = $dbh->prepare_cached($sql) || die;

foreach my $value (@values)
{
    $sth->execute($value);
    while ($sth->fetch) 
    {
     # etc.