title: use union all in rails
body: <p>Is it possible to use <code>union all</code> in rails? I'm putting together a query but I need to use <code>union all</code>, is there any way to adapt it to rails? Here's my query:</p>
  
  <pre><code>select sum(DV.Importe + DV.iva) 
  from venta INNER JOIN DetalleVet DV ON DV.RutaId = [venta].RutaID AND DV.IdEmpresa = [venta].IdEmpresa AND DV.Docto = [venta].Documento 
  where venta.Rutaid=8 and diao=611 and venta.TipoVta='Contado'
  union all 
  select SUM(DP.Importe + DP.Iva) from pedidosliberados PL inner join detallepedidoliberado DP on PL.PEDIDO=DP.PEDIDO and PL.RUTA=DP.RUTA and  PL.IDEMPRESA=DP.idempresa
  where  PL.cancelada=0 and  PL.status=5 and PL.Tipo='Contado' and PL.Ruta=8 and PL.DiaO_entrega=611
  </code></pre>