public function getVisitorIds($customerId)
    {
        $connection = $this->getConnection();

        $select = $connection->select()
            ->from($this->getMainTable(), ['visitor_id'])
            ->where($connection->quoteInto('customer_id = ?', $customerId));

        return array_unique($connection->fetchCol($select));
    }
public function getVisitorIds($customerId)
    {
        $connection = $this->getConnection();

        $select = $connection->select()
            ->from($this->getMainTable(), ['visitor_id'])
            ->where($connection->quoteInto('customer_id = ?', $customerId));

        return array_unique($connection->fetchCol($select));
    }
public function getVisitorIds ( $ customerId ) { $ connection = $ this -> getConnection ( ) ; $ select = $ connection -> select ( ) -> from ( $ this -> getMainTable ( ) , [ 'visitor_id' ] ) -> where ( $ connection -> quoteInto ( 'customer_id = ?' , $ customerId ) ) ; return array_unique ( $ connection -> fetchCol ( $ select ) ) ; }
Retrieve all visitor ids used by a given customer Id.

@param int $customerId The customer Id

@return array
Retrieve all visitor ids used by a given customer Id .