WP Meta Query - mixed AND / OR query doesn't work

Question

I am absolutely boggled by this one.

I am creating a search function for a property site - simple enough. Simple queries such as max_price, max_beds, rent_or_buy work ok. But I am trying to create a keyword match search that can query postcode, project_id and suburb my query comes up empty.

My meta_query argument of WP_Query looks like this;

(
    [relation] => AND
    [0] => Array
        (
            [key] => for_buy_or_rent
            [value] => buy
            [compare] => =
            [type] => CHAR
        )
    [1] => Array
        (
            [relation] => OR
            [0] => Array
                (
                    [key] => project_id
                    [value] => 3066
                    [compare] => LIKE
                    [type] => NUMERIC
                )
            [1] => Array
                (
                    [key] => postcode
                    [value] => 3066
                    [compare] => LIKE
                    [type] => NUMERIC
                )
            [2] => Array
                (
                    [key] => suburb
                    [value] => 3066
                    [compare] => LIKE
                    [type] => CHAR
                )
        )
)

note - I use a switch case to build it on the fly.

Running $projects->request outputs the following SQL;

SELECT SQL_CALC_FOUND_ROWS wp_posts.id 
FROM   wp_posts 
       INNER JOIN wp_postmeta 
               ON ( wp_posts.id = wp_postmeta.post_id ) 
       INNER JOIN wp_postmeta AS mt1 
               ON ( wp_posts.id = mt1.post_id ) 
WHERE  1 = 1 
       AND (( ( wp_posts.post_title LIKE '%3066%' ) 
               OR ( wp_posts.post_excerpt LIKE '%3066%' ) 
               OR ( wp_posts.post_content LIKE '%3066%' ) )) 
       AND ( ( wp_postmeta.meta_key = 'for_buy_or_rent' 
               AND Cast(wp_postmeta.meta_value AS CHAR) = 'buy' ) 
             AND ( ( mt1.meta_key = 'project_id' 
                     AND Cast(mt1.meta_value AS signed) LIKE '%3066%' ) 
                    OR ( mt1.meta_key = 'postcode' 
                         AND Cast(mt1.meta_value AS signed) LIKE '%3066%' ) 
                    OR ( mt1.meta_key = 'suburb' 
                         AND Cast(mt1.meta_value AS CHAR) LIKE '%3066%' ) ) ) 
       AND wp_posts.post_type = 'project' 
       AND ( wp_posts.post_status = 'publish' 
              OR wp_posts.post_status = 'acf-disabled' 
              OR wp_posts.post_status = 'future' 
              OR wp_posts.post_status = 'draft' 
              OR wp_posts.post_status = 'pending' 
              OR wp_posts.post_status = 'private' ) 
GROUP  BY wp_posts.id 
ORDER  BY wp_posts.post_title LIKE '%3066%' DESC, 
          wp_posts.post_date DESC 
LIMIT  0, 24 

If I get rid of the sub-query OR, it works. If I try to use one of the sub queries on the top level AND query, it doesn't match. Check a screenshot of my database to ensure the match is there:

Answer 1

if($search->keyword){
    $project_args['s'] = $search->keyword;
}

That was the culprit. FML!

Everything else was correct.