Thanks for that, but what I'm really looking for is how to use "in" specifically.

For some reason, query() doesn't seem to be returning any results, so I'm now using fetchAll().

So, the following returns all records for user 2:

$sql = 'SELECT * FROM table WHERE user_id in (?)';
$result = $db->fetchAll($sql, 2);

But I want all records for users 2, 3, and 4.