title: Sub grid from same data as main grid
body: <p>I load my main grid data via json (from mysql).</p>
  
  <p>My grid consists of orders. Each order contains a number of items (order lines).</p>
  
  <p>I would like to query all order lines in one query at load. These order lines should be grouped by order id.</p>
  
  <p>This is what I want:
  Main grid: only show one row per id (with totals of the values in sub rows)
  Sub grid: a '+' on each main row. When I click it, the sub grid appears, showing each sub row</p>
  
  <p>Is this possible with jqGrid? Or do I <em>have</em> to do extra queries for the sub grids?</p>
  
  <p>Best regards
  Ole</p>