how to join post meta and taxonomy table wpdb mysql

Question

im writting sql query to get post based on taxonomy and post meta, right now i have this

<?php
$querystr = "
SELECT * 
FROM $wpdb->posts as m,$wpdb->postmeta
LEFT JOIN $wpdb->term_relationships ON(m.ID = $wpdb->term_relationships.object_id)
LEFT JOIN $wpdb->term_taxonomy ON($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id)
LEFT JOIN $wpdb->terms ON($wpdb->term_taxonomy.term_id = $wpdb->terms.term_id)  
WHERE m.post_type = 'holiday' 
AND $wpdb->posts.ID = $wpdb->postmeta.post_id 
AND $wpdb->postmeta.meta_key = 'repeatable_fields' 
AND $wpdb->postmeta.meta_value like '%July%' 
AND m.post_status = 'publish'
AND $wpdb->term_taxonomy.taxonomy = 'location'
AND $wpdb->terms.slug = 'berlin' OR $wpdb->terms.slug = 'canada'
ORDER BY m.post_date DESC
 "; ?>

but it displaying empty result even though i have posts based on the above critirea. individually each table works fine with the query below,

SELECT $wpdb->posts.* 
    FROM $wpdb->posts, $wpdb->postmeta
    WHERE $wpdb->posts.ID = $wpdb->postmeta.post_id 
    AND $wpdb->postmeta.meta_key = 'repeatable_fields' 
    AND $wpdb->postmeta.meta_value like '%July%' 
    AND $wpdb->posts.post_status = 'publish' 
    AND $wpdb->posts.post_type = 'holiday'
    AND $wpdb->posts.post_date < NOW()
    ORDER BY $wpdb->posts.post_date DESC

and for taxonomy

SELECT * 
    FROM $wpdb->posts as m
LEFT JOIN $wpdb->term_relationships ON(m.ID = $wpdb->term_relationships.object_id)
LEFT JOIN $wpdb->term_taxonomy ON($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id)
LEFT JOIN $wpdb->terms ON($wpdb->term_taxonomy.term_id = $wpdb->terms.term_id)  
WHERE m.post_type = 'holiday' 
AND m.post_status = 'publish'
AND $wpdb->term_taxonomy.taxonomy = 'location'
AND $wpdb->terms.slug = 'berlin' OR $wpdb->terms.slug = 'canada'
ORDER BY m.post_date DESC
 ";

but how to join both in a single sql query, hope someone help me on this.

Answer 1

Try with INNER JOIN and join the post_meta table with the additional field meta_key so it will join only the respective rows

SELECT * FROM `wp_posts` wp
INNER JOIN `wp_postmeta` wm ON (wm.`post_id` = wp.`ID` AND wm.`meta_key`='repeatable_fields')
INNER JOIN `wp_term_relationships` wtr ON (wp.`ID` = wtr.`object_id`)
INNER JOIN `wp_term_taxonomy` wtt ON (wtr.`term_taxonomy_id` = wtt.`term_taxonomy_id`)
INNER JOIN `wp_terms` wt ON (wt.`term_id` = wtt.`term_id`)
AND wtt.taxonomy = 'location' AND wt.`slug`IN ('berlin','canada')
AND wp.post_status = 'publish' AND wm.meta_value LIKE '%July%' 
ORDER BY wp.post_date DESC