$this->db->like($this->cat /*cont_cat*/, $cat_id /*например 2*/); 
$this->db->limit($limit, $start_from); // не суть
$query = $this->db->get($this->table); 

        $this->db->order_by('cont_alias', 'desc');
        $query = $this->db->get($this->table);
        $row = $query->row_array();
        $page_cat = $row['cont_cat'];
        $cat_num = explode(",", $page_cat); // формируем массив с категориями
        foreach ($cat_num as $key => $value) {
            if ($cat_id == $value) {
                $this->db->where($this->cat, $cat_id);
                $query = $this->db->get($this->table);
            }
        }
        $this->db->limit($limit, $start_from);
        return $query->result_array();

  $resarray = array();
        
              //$this->db->select($this->cat);
              $this->db->from($this->table);
                $query = $this->db->get(); // Получаем все записи таблицы
                $allcontent = $query->result_array();
                foreach ($allcontent as $key => $value ){
                    foreach ($value as $keysub['cont_cat'] => $valuesub) {
                        $cat_num = explode(",", $valuesub); // массив id категорий $valuesub
                    
                    foreach ($cat_num as $key2 => $value2){
                        if($value2 == $cat_id){ // сравниваем нашу категорию
                            $resarray = $resarray + $allcontent[$key];
    
                            }
                    
                        }
                    }
                }

    public function get_page($cat_id, $limit, $start_from=0)
    {

        $resarray = array();
        
              //$this->db->select($this->cat);
              $this->db->from($this->table);
                $query = $this->db->get(); // Получаем все записи таблицы
                $allcontent = $query->result_array();

                foreach ($allcontent as $key => $value ){
                    foreach ($value as $keysub => $valuesub) {
                        
                        if ($keysub=='cont_cat'){
                             $cat_num = explode(",", $valuesub); // массив id категорий $valuesub
                             foreach ($cat_num as $key2 => $value2){
                                if($value2 == $cat_id){
                                   $this->db->or_where('cont_id', $value['cont_id']);
                                    
                                    }
                    
                        }
                            
                        }
                       
                    
             
                    }
                }
                
                
                
                $this->db->limit($limit, $start_from);
                $query = $this->db->get($this->table);
                return  $query->result_array();
                
             

   
    }

 public function get_page($cat_id, $limit, $start_from = 0)
    {

        $resarray = array();

        $this->db->from($this->table);
        $query = $this->db->get(); // Получаем все записи таблицы
        $allcontent = $query->result_array();

        foreach ($allcontent as $key => $value) {
            foreach ($value as $keysub => $valuesub) {

                if ($keysub == 'cont_cat') {
                    $cat_num = explode(",", $valuesub); // массив id категорий $valuesub
                    foreach ($cat_num as $key2 => $value2) {
                        if ($value2 == $cat_id) {
                            $this->db->or_where('cont_id', $value['cont_id']);

                        }

                    }

                }


            }
        }


        $this->db->limit($limit, $start_from);
        $query = $this->db->get($this->table);
        return $query->result_array();


    }

    public function get_page($cat_id, $limit, $start_from = 0)
    {

        $resarray = array();

        //$this->db->select($this->cat);
        $this->db->where('cat_id', $cat_id);
        $this->db->from('t_sv');
        $query = $this->db->get(); // Получаем все записи таблицы
        $allcontent = $query->result_array();
        foreach ($allcontent as $key => $value) {

            $this->db->or_where('cont_id', $value['cont_id']);
        }


        $this->db->limit($limit, $start_from);
        $query = $this->db->get('t_content');
        return $query->result_array();


    }

    public function get_page($cat_id, $limit, $start_from = 0)
    {
        $this->db->limit($limit, $start_from);
        $this->db->select('co.*');
        $this->db->from('t_sv sv');
        $this->db->join('t_content co', 'sv.cont_id = co.cont_id');
        $this->db->or_where('sv.cat_id', $cat_id);
        $query = $this->db->get();
        return $query->result_array();
    }

        select ='c.cont_id,c.cont_title,c.cont_alias,c.cont_state,n.cat_title,c.cont_hits,c.cont_id_author,c.cont_date,c.cont_date_mod';      
        $this->db->select($select);
        $this->db->from('t_sv sv'); 
        $this->db->join('t_content c', 'sv.cont_id = c.cont_id');
        $this->db->join('t_category n', 'sv.cat_id = n.cat_id');