the error i was making is with the quotes.
select * from table where name = ':name'
is not correct. you need to remove the quotes
select * from table where name = :name
so if you want to use multiple just array nest them
$db->exec(
`select * from table where first_name = :fname and last_name = :lname`,
array(
':fname' => 'xero',
':lname' => 'harrison'
)
);
maybe this will help someone else.