Custom query: Get posts by one custom field, ORDER BY another custom field?

For an event calendar I’m retrieving posts from a certain category by custom fields. The start date custom field name is start-date, end date, you guessed it: end-date

It retrieves posts with an end date >= now, and should order the output by the end date.

I’m using the query below. There’s 2 LEFT JOIN’s in there to provide the value for the start and end date. Is there a better way to do this?

$querystr = "
SELECT * FROM $wpdb->posts
LEFT JOIN $wpdb->postmeta AS eventend ON(
$wpdb->posts.ID = eventend.post_id
)
LEFT JOIN $wpdb->postmeta AS eventstart ON(
$wpdb->posts.ID = eventstart.post_id
)
LEFT JOIN $wpdb->term_relationships ON($wpdb->posts.ID = $wpdb->term_relationships.object_id)
LEFT JOIN $wpdb->term_taxonomy ON($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id)
WHERE $wpdb->term_taxonomy.taxonomy = 'category'
AND $wpdb->term_taxonomy.term_id = 23
AND $wpdb->posts.post_status = 'published'
AND eventend.meta_key = 'event-end'
AND eventend.meta_value >= NOW()
AND eventstart.meta_key = 'event-start'
ORDER BY eventstart.meta_value ASC
";

$eventlist = $wpdb->get_results($querystr, OBJECT);
?>