Database Query Problem please help

[eluser]gork7478[/eluser]
I have this problem and I'm trying to figure out what I'm doing wrong. I like to write out my queries, my own personal preference of course. If I do this:

Code:

$this->db->where('key', $key);
$query = $this->db->get('temp_users');

It works fine no problem.
But if I do this

Code:

$sql = 'SELECT * FROM temp_users WHERE key=? LIMIT 1';
$query = $this->db->query($sql, array('key' => $key));

It tells me to check my MySql syntax. Please tell if these two bits of code don't do the same thing.