php - how to display newest items from 4 tables in codeigniter -

i created div on homepage display recent items 4 tables on database, i'm having problems structure of query, tried model:

   $sql = "(select name,type, screenshot,url music status = 1   )      union (select name,type, screenshot,url lyrics status = 1   )     union all(select name,type, screenshot,url mixtapes status = 1  )      union (select name,type, screenshot, vurl videos  status = 1  ) order 'date_added' desc limit 8";      $query = $this->db->query($sql);      return $query->result();   

this query retrieves music table, , limit keyword applies items retrieved music table, want query run 1 query, items retrieved based on latest items 4 tables , limit keyword limits results 8 items, please how construct query, or there other way it? please help..

if want 2 recent items of each list; can use this:

(select name,type, screenshot,url music      status = 1 order date_added desc limit 0,2)  union (select name,type, screenshot,url lyrics       status = 1 order date_added desc limit 0,2) union (select name,type, screenshot,url mixtapes      status = 1 order date_added desc limit 0,2)  union (select name,type, screenshot,url videos      status = 1 order date_added desc limit 0,2)  

or, if want recent 8 items 4 tables:

select * (     (select name,type, screenshot,url music status = 1)      union     (select name,type, screenshot,url lyrics status = 1)      union     (select name,type, screenshot,url mixtapes status = 1)      union     (select name,type, screenshot,url videos status = 1)  ) order date_added desc limit 0,8;