I have 3 joined tables - The query search some string on main table then join other by entity_id. I want to orderBy records in order first second third tables result, but no success now. At this time I have order by only for main table.

My query:

    
    $query = db_select('field_data_field_cg_w', 'w');
    
    $query -> join('field_data_field_cg_h', 'h', 'w.entity_id = h.entity_id');
    $query -> fields('h', array('entity_id', 'field_cg_h_value'));
    
    $query -> join('field_data_field_cg_g', 'g', 'w.entity_id = g.entity_id');
    $query -> fields('g', array('entity_id', 'field_cg_g_value'));
    
    $query -> fields('w', array('entity_id', 'field_cg_w_value'))
      -> condition('w.field_cg_w_value', $options['string'] . '%', 'LIKE')
      -> orderBy('w.field_cg_w_value', 'ASC');
    
    $records = $query->execute();

EDIT:
The result (last part of query) after Clive's answer:

    
    $query -> fields('w', array('entity_id', 'field_cg_w_value'))
      -> condition('w.field_cg_w_value', $options['string'] . '%', 'LIKE')
      -> orderBy('w.field_cg_w_value', 'ASC')
      -> orderBy('h.field_cg_h_value', 'ASC')
      -> orderBy('g.field_cg_g_value', 'ASC');