錯誤編號：1066不是唯一的表/別名：'posts'SELECT * FROM (SELECT id, title, keywords, 'posts' AS type FROM posts, postsUNION SELECT id, title, keywords, 'android' AS type FROM android, androidUNION SELECT id, title, keywords, 'mac' AS type FROM mac, mac)t WHERE t.title like '%yj% ' OR t.keywords LIKE '%yj%'模型：  $query = $this->input->GET('search', TRUE);  $this->db->select("id, title, keywords, 'posts' AS type");  $this->db->from("posts");  $query1 = $this->db->get_compiled_select('posts');  $this->db->select("id, title, keywords, 'android' AS type");  $this->db->from("android");  $query2 = $this->db->get_compiled_select('android');  $this->db->select("id, title, keywords, 'mac' AS type");  $this->db->from("mac");  $query3 = $this->db->get_compiled_select('mac');  $data = $this->db->query('SELECT * FROM (' . $query1 . ' UNION ' . $query2 . ' UNION ' . $query3 . ')' . "t WHERE t.title like '%$query%' OR t.keywords LIKE '%$query%'");         return $data->result();