Maggie's Farm

Query failed:

SELECT  c.categoryid,
                           c.category_name,
                           c.category_icon,
                           c.category_description,
                           c.authorid,
                           c.category_left,
                           c.category_right,
                           c.parentid,

                           a.username,
                           a.username AS loginname,
                           a.realname
                      FROM csg_category AS c
           LEFT OUTER JOIN csg_authors AS a
                        ON c.authorid = a.authorid
           LEFT OUTER JOIN csg_authorgroups AS ag
                        ON ag.authorid = c.authorid
           LEFT OUTER JOIN csg_access AS acl
                        ON (ag.groupid = acl.groupid AND acl.artifact_id = c.categoryid)
                           
                           GROUP BY c.categoryid
 ORDER BY category_name ASC

/ Got error 28 from storage engine