(SELECT
    wp_posts.ID AS 'id',
    wp_posts.post_title AS 'item',
    wp_posts.post_excerpt AS 'title',
    wp_terms.slug AS 'link',
    wp_posts.menu_order AS 'order',
    wp_terms.name AS 'title2',
    'category' AS 'type'
FROM wp_posts
LEFT JOIN  wp_term_relationships ON wp_posts.ID = wp_term_relationships.object_id
LEFT JOIN wp_postmeta ON wp_posts.ID = wp_postmeta.post_id
LEFT JOIN wp_postmeta AS t ON id = t.post_id
INNER JOIN wp_terms ON t.meta_value = wp_terms.term_id 
WHERE post_type = 'nav_menu_item' 
    AND wp_term_relationships.term_taxonomy_id = 15
    AND post_status = 'publish'
    AND wp_postmeta.meta_value = 'category'
    AND t.meta_key =  '_menu_item_object_id'
ORDER BY wp_posts.menu_order)

UNION

(SELECT 
    f.ID AS 'id',
    f.post_title AS 'item',
    f.post_excerpt AS 'title',
    s.post_name AS 'link',
    f.menu_order AS 'order',
    f.post_excerpt AS 'title2',
    'page' AS 'type'
FROM `wp_posts` AS f
LEFT JOIN  wp_term_relationships ON f.ID = wp_term_relationships.object_id
LEFT JOIN  `wp_posts` AS s ON s.ID = (
            SELECT `meta_value` FROM `wp_postmeta` 
            WHERE `post_id` = f.ID AND `meta_key` = '_menu_item_object_id'
            )
WHERE f.post_type = 'nav_menu_item' 
    AND wp_term_relationships.term_taxonomy_id = 15
    AND f.post_status = 'publish'
    AND s.post_type = 'page'
ORDER BY f.menu_order)

UNION

(SELECT
    wp_posts.ID AS 'id',
    wp_posts.post_title AS 'item',
    wp_posts.post_excerpt AS 'title',
    t.meta_value AS 'link',
    wp_posts.menu_order AS 'order',
    wp_terms.name AS 'title2',
    'link' AS 'type'
FROM wp_posts
LEFT JOIN  wp_term_relationships ON wp_posts.ID = wp_term_relationships.object_id
LEFT JOIN wp_postmeta AS t ON id = t.post_id
LEFT JOIN wp_terms ON t.meta_value = wp_terms.term_id 
WHERE post_type = 'nav_menu_item' 
    AND wp_term_relationships.term_taxonomy_id = 15
    AND post_status = 'publish'
    AND t.meta_key =  '_menu_item_url'
    AND t.meta_value != ''
ORDER BY wp_posts.menu_order)

ORDER BY `order`;