concat in mysql using codeigniter

Question

In my application every user can like every comment.But each like is entered as comma seperated form.User id of each users like entered into database as 2,4,5..etc.I use concat in my model like this

        public function shop_like($shop_id,$user_id,$logged_id)
        { 
            $this->db->where('user_id',$user_id);

            $this->db->where('shop_id', $shop_id);
            $this->db->set('review_like', 'review_like+1', FALSE);
            $where = "CONCAT('like_user_id', ',','".$logged_id."')"; 
           // $where = CONCAT(like_user_id,'".$logged_id."');
            $this->db->set('like_user_id', $where);
            $this->db->set('review_like', 'review_like+1', FALSE);
            $this->db->update('shop_reviews',$data);
          }

Each like, the like_user_id field contain the inserted value like this CONCAT(like_user_id, ',','7') this is the problem

I want the existing comma seperated values and the user id of liked user

plzz correct the syntax of concat

Answer 1

如果要更新列，请使用set()而不要在where子句中使用：

$this->db->set("like_user_id", "CONCAT( like_user_id, ',".$logged_id."' )", false);

Answer 2

Use below code

    public function shop_like($shop_id,$user_id,$logged_id)
    { 
        $this->db->where('user_id',$user_id);

        $this->db->where('shop_id', $shop_id);
        $this->db->set('review_like', 'review_like+1', FALSE);
        $where = "CONCAT(like_user_id, ',','".$logged_id."')"; 
        $this->db->set('like_user_id', $where, false);
        $this->db->set('review_like', 'review_like+1', FALSE);
        $this->db->update('shop_reviews',$data);
      }