gistfile1.php

<?php

$dbh = new PDO(/* connection details */);

$query = '
    SELECT *
    FROM table
    WHERE col1 = :value1
    AND col2 = :value2
';
$params = array(
    'value1' => 'foo',
    'value2' => 'bar'
);

$statement = $dbh->prepare($query);
$statement->execute($params);

while ($row = $statement->fetch(PDO::FETCH_ASSOC)) {
    // ...
}