everyeurocounts on "$wpdb Inner Join"

I am trying to create a array of postdates where the post meets a custom taxonomy criteria (location) this will also be modified by a form element (will be using Ajax hopefully) but im stuck on creating the array.

Basically using INNER JOIN to match the two tables and select the postdate from wp_posts where the taxomomy id = 3 (this links to another table with the text format of the taxonomy name).

$fdates = $wpdb->get_results("SELECT post_date FROM wp_posts INNER JOIN wp_term_realtionships
		ON wp_terms_relationships.object_id=wp_posts.object_id
		WHERE wp_terms_relationships.term_taxonomy_id = 3");

it just returns array() using print_r function.
Localhost so no example :( Thanks in advance to anyone who can help me!