MySQL query for wordpress meta data - mysql

Question

I need some help with a query that should return posts based on their wp-postratings score (http://wordpress.org/extend/plugins/wp-postratings/).
The user chooses a minimum rating (0 to 5 stars) and a maximum rating (0 to 5 stars) and the query should return the posts that match. I have it working where the user input for both values is above 0 but I can't seem to get my head around the 0 value. Since 0 represents unrated posts - and hence onces that have no ratings meta data - I need to select not only the posts where the rating is no more than the specified max value, but also every post that has no rating meta data.
How can I do this?? Any help will be very much appreciated!
Here's my current query:
SELECT DISTINCT p.*, (t1.meta_value+0.00) AS ratings_average, (t2.meta_value+0.00) AS ratings_users, (t3.meta_value+0.00) AS ratings_score
FROM wp_posts p
INNER JOIN wp_term_relationships tr ON (p.ID = tr.object_id)
INNER JOIN wp_term_taxonomy tt ON (tr.term_taxonomy_id = tt.term_taxonomy_id)
INNER JOIN wp_terms t ON t.term_id = tt.term_id
LEFT JOIN wp_postmeta AS t1 ON t1.post_id = p.ID
LEFT JOIN wp_postmeta AS t2 ON t1.post_id = t2.post_id
LEFT JOIN wp_postmeta AS t3 ON t3.post_id = p.ID
WHERE t1.meta_key = 'ratings_average'
AND t2.meta_key = 'ratings_users'
AND t3.meta_key = 'ratings_score'
AND p.post_date < NOW()
AND p.post_status = 'publish'
AND (tt.taxonomy = 'post_tag' AND tt.term_id = t.term_id AND t.slug = 'liverpool')
AND ( (t1.meta_value+0.00) IS NULL OR (t1.meta_value+0.00) <= $max_stars )
ORDER BY p.post_date DESC
LIMIT 20

Answer 1

I had to do something similar a while back where I was running a cron job to send posts to another application that weren't already registered. The best method I found was to write a query that checked that the ID was NOT IN a query of posts with the meta key.
SELECT $wpdb->posts.ID
FROM $wpdb->posts
WHERE $wpdb->posts.post_status = 'publish'
AND $wpdb->posts.post_type = 'post'
AND $wpdb->posts.ID NOT IN (
SELECT $wpdb->posts.ID
FROM $wpdb->posts
left join $wpdb->postmeta ON ($wpdb->posts.ID = $wpdb->postmeta.post_id)
WHERE $wpdb->posts.post_status = 'publish'
AND $wpdb->postmeta.meta_key = 'meta_key')
I believe this should work, though I obviously haven't tested it.
SELECT DISTINCT p.*, (t1.meta_value+0.00) AS ratings_average, (t2.meta_value+0.00) AS ratings_users, (t3.meta_value+0.00) AS ratings_score
FROM wp_posts p
INNER JOIN wp_term_relationships tr ON (p.ID = tr.object_id)
INNER JOIN wp_term_taxonomy tt ON (tr.term_taxonomy_id = tt.term_taxonomy_id)
INNER JOIN wp_terms t ON t.term_id = tt.term_id
LEFT JOIN wp_postmeta AS t1 ON t1.post_id = p.ID
LEFT JOIN wp_postmeta AS t2 ON t1.post_id = t2.post_id
LEFT JOIN wp_postmeta AS t3 ON t3.post_id = p.ID
WHERE t1.meta_key = 'ratings_average'
AND t2.meta_key = 'ratings_users'
AND t3.meta_key = 'ratings_score'
AND p.post_date < NOW()
AND p.post_status = 'publish'
AND (tt.taxonomy = 'post_tag'
AND tt.term_id = t.term_id
AND t.slug = 'liverpool')
AND (
p.ID NOT IN (
SELECT p.ID
FROM wp_posts AS p
LEFT JOIN wp_postmeta AS pm ON (pm.post_id = p.ID)
WHERE pm.meta_key = 'ratings_score'
)
OR
(t1.meta_value+0.00) <= $max_stars )
ORDER BY p.post_date DESC
LIMIT 20

Answer 2

Okay, this query seems to work for me. Its a bit ugly though and not too quick so if anyone has a better one feel free to improve upon it!
It selects all of the rated posts that are below the $max_stars value, then combines the table with a separate select which gets all of the non-rated posts:
(SELECT DISTINCT p.*, (t1.meta_value+0.00) AS ratings_average, (t2.meta_value+0.00) AS ratings_users, (t3.meta_value+0.00) AS ratings_score
FROM wp_posts p
INNER JOIN wp_term_relationships tr ON (p.ID = tr.object_id)
INNER JOIN wp_term_taxonomy tt ON (tr.term_taxonomy_id = tt.term_taxonomy_id)
INNER JOIN wp_terms t ON t.term_id = tt.term_id
LEFT JOIN wp_postmeta AS t1 ON t1.post_id = p.ID
LEFT JOIN wp_postmeta AS t2 ON t2.post_id = p.ID
LEFT JOIN wp_postmeta AS t3 ON t3.post_id = p.ID
WHERE t1.meta_key = 'ratings_average'
AND t2.meta_key = 'ratings_users'
AND t3.meta_key = 'ratings_score'
AND p.post_date < NOW()
AND p.post_status = 'publish'
AND (tt.taxonomy = 'post_tag' AND tt.term_id = t.term_id AND t.slug = 'liverpool')
AND (t1.meta_value+0.00) <= $max_stars )
UNION
(SELECT DISTINCT p.*, NULL AS ratings_average, NULL AS ratings_users, NULL AS ratings_score
FROM wp_posts p
INNER JOIN wp_term_relationships tr ON (p.ID = tr.object_id)
INNER JOIN wp_term_taxonomy tt ON (tr.term_taxonomy_id = tt.term_taxonomy_id)
INNER JOIN wp_terms t ON t.term_id = tt.term_id
LEFT JOIN wp_postmeta AS t1 ON (t1.post_id = p.ID AND t1.meta_key = 'ratings_score')
WHERE t1.post_id is null
AND p.post_date < NOW()
AND p.post_status = 'publish'
AND (tt.taxonomy = 'post_tag' AND tt.term_id = t.term_id AND t.slug = 'liverpool') )
ORDER BY post_date DESC