Failed to execute the SQL query

select  f.id, f.name, count(*) from  gregarius_channels  c inner join  gregarius_folders  f on f.id = c.parent  where f.name != ''  and not (c.mode & 4) group by f.id  order by f.position asc, c.position asc

Error 1055: Expression #2 of ORDER BY clause is not in GROUP BY clause and contains nonaggregated column 'db100786_rss_cheval.c.position' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by