Views with node references result redundant records
I have found the most possible answer. It may need to update the query from hook_views_query_alter(). The generated query from views is here :

SELECT node.nid AS nid, 
    field_transport_node.nid AS field_transport_node_nid, 
    field_transport_node__field_data_field_price.field_price_value AS field_transport_node__field_data_field_price_field_price_val, 
    node.created AS node_created, 
    'node' AS field_data_field_dept_time_node_entity_type, 
    'node' AS field_data_field_travel_time_node_entity_type, 
    'node' AS field_data_field_transport_type_node_entity_type, 
    'node' AS field_data_field_price_node_entity_type, 
    'node' AS field_data_field_travel_optr_node_entity_type, 
    'node' AS field_data_field_ticket_office_node_entity_type
FROM 
{node} node
LEFT JOIN {field_data_field_transport} field_data_field_transport ON node.nid = field_data_field_transport.field_transport_nid
LEFT JOIN {node} field_transport_node ON field_data_field_transport.entity_id = field_transport_node.nid
LEFT JOIN {field_data_field_leg} field_data_field_leg ON node.nid = field_data_field_leg.entity_id AND (field_data_field_leg.entity_type = 'node' AND field_data_field_leg.deleted = '0')
LEFT JOIN {field_data_field_price} field_transport_node__field_data_field_price ON field_transport_node.nid = field_transport_node__field_data_field_price.entity_id AND (field_transport_node__field_data_field_price.entity_type = 'node' AND field_transport_node__field_data_field_price.deleted = '0')
WHERE (( (node.status = '1') AND (node.type IN  ('transport')) AND (field_data_field_leg.field_leg_nid = '2' ) ))
ORDER BY field_transport_node__field_data_field_price_field_price_val ASC, node_created DESC
LIMIT 20 OFFSET 0


I just need to add a condition with "OR". It gives me the correct result.

AND ( ( field_transport_node.nid IS NOT NULL AND field_price_value IS NOT NULL ) OR ( field_transport_node.nid IS NULL AND field_price_value IS  NULL ) )


How can I add this kind of OR condition from views UI ?
How can I do it with query object of the views ?

function mymodule_views_query_alter(&amp;$view, &amp;$query){
    switch($view-&gt;name){
        case 'my_view_name' :   
            $query-&gt;where[0]['conditions'][] = array(
                'field' =&gt; '',
                'value' =&gt; '',
                'operator' =&gt; ''
            );
            break;
    }
}