不是唯一的表/别名（codeigniter）

Question

错误编号：1066不是唯一的表/别名：'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();

Answer 1

删除表的所有第二个名称并使用 UNION ALL 代替：

SELECT * FROM (

  SELECT id, title, keywords, 'posts' AS type FROM  posts 

  UNION ALL 

  SELECT id, title, keywords, 'android' AS type FROM android 

  UNION ALL 

  SELECT id, title, keywords, 'mac' AS type FROM mac

)t WHERE t.title like '%yj%' OR t.keywords LIKE '%yj%'