Codeigniter: error Cannot use object of type CI_DB_mysqli_result as array

You probably used the wrong variable. Try this:

public function move($data)
{
    $sku = $data['sku'];
    $store = $data['store_id'];
    $sql = "SELECT * FROM products WHERE sku = ? AND store_id = ?";
    $query = $this->db->query($sql, array($data['sku'], $data['store_id']));
    $result_array = $query->result_array();
    if($result_array) {
        $data['qty'] =  $data['qty'] + $result_array['qty'] ;  //Error here
        $insert = $this->db->query('products', $data);
        return ($insert == true) ? true : false;
    }
    else{

    }
}

$query->result_array() will return an array of rows from database which satisfies the query condition. If you need only one row, you have to modify it.

public function move($data)
{
    $sku = $data['sku'];
    $store = $data['store_id'];
    $sql = "SELECT * FROM products WHERE sku = ? AND store_id = ?";
    $query = $this->db->query($sql, array($data['sku'], $data['store_id']));

if($query->num_rows() > 0){
    $row = $query->row();  // select only first row of the query result
    $data['qty'] =  $data['qty'] + $row['qty'] ;
    $insert = $this->db->query('products', $data);  // don't know what you are doing here
    return ($insert == true) ? true : false;
}else{
}
}

In the mysqli_result class

• Represents the result set obtained from a query against the database.

Here Mostly use two types

1. set of Array items
2. single row

In the format of using mysqli_result Class their are two methods of using to extract the result in above mentioned categories:

`1-mysqli_result::fetch_array — Fetch the next row of a result set as an associative, a numeric array, or both`

`2-mysqli_result::fetch_row — Fetch the next row of a result set as an enumerated array`

Here is the simple solution in Php Codeigniter:-

I have also face this problem when calling to

1-example"-

$registrations = $this->db->get_where('registration', array('school_id' => school_id()))

then just write solution

->result_array(); or ->row_array();

like this:-

$registrations = $this->db->get_where('registration', array('school_id' => school_id()))->result_array(); 

Problem Solved!