Подскажите как исправить. Когда пытаюсь вызвать страницу с view union - выходит следующее сообщение. В чем может быть ошибка.

user warning: Unknown column 'comments.timestamp' in 'field list' query: SELECT COUNT(*) FROM ((SELECT node.nid, comments.timestamp AS comments_timestamp_timestamp FROM node node LEFT JOIN votingapi_cache votingapi_cache_vote_points_sum ON node.nid = votingapi_cache_vote_points_sum.content_id AND votingapi_cache_vote_points_sum.content_type = 'node' AND votingapi_cache_vote_points_sum.value_type = 'points' AND votingapi_cache_vote_points_sum.tag = 'vote' AND votingapi_cache_vote_points_sum.function = 'sum' WHERE (node.type IN ('blog')) AND (node.status = '1') AND (votingapi_cache_vote_points_sum.value > 1) ORDER BY node_created_created DESC) UNION (SELECT node.nid, comments.timestamp AS comments_timestamp_timestamp FROM node node WHERE (node.type IN ('blog')) AND (node.status = '1') AND (node.sticky = '1') ORDER BY node_created_created DESC)) AS sq in Z:\home\localhost\www\shvabr\includes\database.mysql.inc on line 172.