SELECT p.`ID`, p.`post_title`, p.`post_excerpt`, p.`post_content`
, m1.`meta_value` AS `info`
, m2.`meta_value` AS `spec`
, m3.`meta_value` AS `ip_cam`
, m4.`meta_value` AS `func`
, GROUP_CONCAT( t.`name` order by `t`.`name` SEPARATOR ',' ) AS `tags`
FROM `wp_posts` p
LEFT JOIN `wp_postmeta` m1 ON p.ID = m1.post_id AND m1.`meta_key`= '_product_info_subtitle'
LEFT JOIN `wp_postmeta` m2 ON p.ID = m2.post_id AND m2.`meta_key`= '_product_specification_ip_cam'
LEFT JOIN `wp_postmeta` m3 ON p.ID = m3.post_id AND m3.`meta_key`= '_product_specification_ip_cam_group'
LEFT JOIN `wp_postmeta` m4 ON p.ID = m4.post_id AND m4.`meta_key`= '_product_icons_function'
LEFT JOIN `wp_term_relationships` tr ON p.ID = tr.object_id
LEFT JOIN `wp_term_taxonomy` tt ON tr.term_taxonomy_id = tt.term_taxonomy_id
LEFT JOIN `wp_terms` t ON tt.term_id = t.term_id
WHERE p.post_type = 'product'
GROUP BY p.`ID`