Question

I need to agregate a table before joining it with other tables.

wp_postmeta GROUP BY wp_postmeta.post_id

Is it possible? Where should I put it in? Here is my code:

SELECT wp_posts.post_content, wp_posts.ID, wp_terms.slug
FROM wp_posts
JOIN wp_postmeta ON wp_posts.ID = wp_postmeta.post_id
JOIN wp_term_relationships ON wp_posts.ID = wp_term_relationships.object_id
JOIN wp_term_taxonomy ON wp_term_relationships.term_taxonomy_id = wp_term_taxonomy.term_taxonomy_id
JOIN wp_terms ON wp_term_taxonomy.term_id = wp_terms.term_id


WHERE wp_posts.post_type = 'my-type'
   AND wp_posts.post_status = 'publish'
   AND wp_terms.slug IN
      ('field1', 'field2', 'field3')
   AND
   (
        wp_postmeta.meta_key = 'exclude' AND wp_postmeta.meta_value <> '111'
        OR wp_postmeta.meta_key = 'include' AND wp_postmeta.meta_value = '22'
        OR wp_postmeta.meta_key <> 'include' AND wp_postmeta.meta_key <> 'exclude'
   )

Found a new way of doing it while testing ruakh example. I don’t know why it works, but it does:

SELECT wp_posts.post_content, wp_posts.ID, wp_terms.slug
FROM wp_posts
JOIN wp_term_relationships ON wp_posts.ID = wp_term_relationships.object_id
JOIN wp_term_taxonomy ON wp_term_relationships.term_taxonomy_id = wp_term_taxonomy.term_taxonomy_id
JOIN wp_terms ON wp_term_taxonomy.term_id = wp_terms.term_id
WHERE wp_posts.post_type = 'my-type'
   AND wp_posts.post_status = 'publish'
   AND wp_terms.slug IN
      ('field1', 'field2', 'field3')
   AND NOT wp_posts.id IN                # ADDED NOT
   (
      SELECT wp_postmeta.post_id
        FROM wp_postmeta
        WHERE wp_postmeta.meta_key = 'exclude' AND wp_postmeta.meta_value = '111'  #SINCE NOT ABOVE I CHANGED <> to =
           OR wp_postmeta.meta_key = 'include' AND wp_postmeta.meta_value <> '22'  #SINCE NOT ABOVE I CHANGED = to <>
           #I DELETED THIS LINE
   )

Now the query gives back data if include or exclude isn’t set. And if they are it checks the ID.

Any comments on my change?

MORE IMPROVEMENTS:

SELECT wp_posts.post_content, wp_posts.ID, wp_terms.slug
FROM wp_posts
JOIN wp_term_relationships ON wp_posts.ID = wp_term_relationships.object_id
JOIN wp_term_taxonomy ON wp_term_relationships.term_taxonomy_id = wp_term_taxonomy.term_taxonomy_id
JOIN wp_terms ON wp_term_taxonomy.term_id = wp_terms.term_id

WHERE wp_posts.post_type = 'my-type'
AND wp_posts.post_status = 'publish'
AND wp_terms.slug IN
('field1', 'field2', 'field3')

AND wp_posts.id NOT IN
(
SELECT wp_postmeta.post_id
FROM wp_postmeta

WHERE wp_postmeta.meta_key = 'exclude'
AND wp_postmeta.meta_value IN
('$id', '$id,%', '%,$id,%', '%,$id')

OR wp_postmeta.meta_key = 'include' 
AND wp_postmeta.meta_value NOT IN
('$id', '$id,%', '%,$id,%', '%,$id')

Example of what the wp_postmeta table might look like:

Senario 1 – Only pages with id 18 shall get the data:

meta_id     post_id     meta_key    meta_value
1           30          include     18
2           30          _edit_lock  1322225789:1
3           30          _edit_last  1

Senario 2 -Pages with id 18 shall not get the data:

meta_id     post_id     meta_key    meta_value
1           30          exclude     18
2           30          _edit_lock  1322225789:1
3           30          _edit_last  1

Senario 1 – All pages shall get the data:

meta_id     post_id     meta_key    meta_value
2           30          _edit_lock  1322225789:1
3           30          _edit_last  1

Answer 1

I don’t think you should be doing a real join to wp_postmeta at all, since you don’t actually need anything from it; rather, you should perform a “semi-join”, using an IN or EXISTS clause. For example:

SELECT wp_posts.post_content, wp_posts.ID, wp_terms.slug
FROM wp_posts
JOIN wp_term_relationships ON wp_posts.ID = wp_term_relationships.object_id
JOIN wp_term_taxonomy ON wp_term_relationships.term_taxonomy_id = wp_term_taxonomy.term_taxonomy_id
JOIN wp_terms ON wp_term_taxonomy.term_id = wp_terms.term_id
WHERE wp_posts.post_type = 'my-type'
   AND wp_posts.post_status = 'publish'
   AND wp_terms.slug IN
      ('field1', 'field2', 'field3')
   AND wp_posts.id IN
   (
      SELECT DISTINCT wp_postmeta.post_id
        FROM wp_postmeta
        WHERE wp_postmeta.meta_key = 'exclude' AND wp_postmeta.meta_value <> '111'
           OR wp_postmeta.meta_key = 'include' AND wp_postmeta.meta_value = '22'
           OR wp_postmeta.meta_key <> 'include' AND wp_postmeta.meta_key <> 'exclude'
   )