Problem with JOIN in Custom Select Query

Hi,
I realised today that some of the events that should have been showing up on a website weren’t, and eventually realised the reason was because that ‘term_taxonomy_id’ in the ‘wp_term_relationships’ table is not always the same value as the ‘category_id’. Strangely those two fields matched for the first year the site was running but have now fallen out of sync. So, I now need to match the ‘category_id’ to the ‘terms_id’ field in the ‘wp_term_taxonomy’ table, which is linked to the ‘wp_term_relationships’ table via the ‘term_taxonomy_id’ field. Does that all make sense?

So, I’ve tried adding an extra join to my custom select query but now it’s returning no values. I’ve tried all kinds of different joins but still no luck. Does anyone know what I’m doing wrong? Here’s the SQL query below, which includes the extra LEFT JOIN for this new field.

$category_ID = get_category_id(single_cat_title("", false));
$sql = "SELECT post_id,
DATE_FORMAT(start,'%m/%d/%Y') AS eventStart,
DATE_FORMAT(end,'%m/%d/%Y') AS eventEnd,
DATE_FORMAT(CURDATE(),'%m/%d/%Y') AS today,
DATE_FORMAT(DATE_ADD(CURDATE(), INTERVAL 7 DAY),'%m/%d/%Y') AS endWeek
	FROM   wp_ec3_schedule s
	JOIN   wp_posts p ON p.ID = s.post_id
	JOIN   wp_term_relationships t ON t.object_id = s.post_id
	LEFT JOIN wp_term_taxonomy x ON x.term_taxonomy_id = t.term_taxonomy_id
	WHERE   post_status = 'publish' AND term_taxonomy_id = $category_ID AND end > CURDATE()";
$sql .= ' ORDER BY start ASC';
$sql .=	' LIMIT 0, 10';

Once I have this query working I was then going to change ‘term_taxonomy_id’ to ‘term_id’ in my WHERE clause, which should then bring all the correct values. But for now, I just want to get some records back. What’s wrong with my query?

Cheers,
Russ