sql 一对多，并且合并多的那字段

SELECT
                        wa.id AS album_id,
                        om.truename AS author,
                        wa.title AS albumTitle,
                        wac.title AS categoryTitle,
                        wa.createtime AS postTime,
												(select GROUP_CONCAT(wap.url) FROM web_album_photos wap where wap.album_id=wa.id) as imgurls
                    FROM
                        web_albums  wa
                        left join web_album_categories  wac on wac.id = wa.category_id
                        left join organization_members  om on wa.user_id = om.id
												
                    WHERE
                        wa.organization_id IN ( 22 )
                        AND wa.visable != 1
                    ORDER BY
                        wa.createtime DESC
                        LIMIT 0,
                        15