html - Multiply column values and display them

Question

I am trying to run a query of an orders table to find an order number based on a user given id and then give a total for the order based on the quantity * price. I have the following

 @ordertotals = Orderlines.where(id: @orderinfo.id).sum("quantity * price")

which would place the total in to a new object for each one. I am then trying to display all of the values found to do that I have

<table border=1>
  <tr>
    <td>Order Number</td>
    <td>Order Date</td>
    <td>Cost of Order</td>
  </tr>
    <% # for each customer who has this sales rep
  # display each customer in a row
  for @custdata in @orderinfo   %>
              <tr>
                    <td><%=@orderinfo.id%></td>
                    <td><%=@orderinfo.order_date%></td>
            <% for @orderinfo in @ordertotals %>
                    <td><%=@ordertotals%></td>
            </tr>
            <% end %>
    <% end %>
</table>

Which would loop through the @orderinfo first to display the id and order date then loop through the @ordertotals to display each total. However when I run this I get compiler errors on the

@ordertotals = Orderlines.where(id: @orderinfo.id).sum("quantity * price")

line, could anyone tell me what I am doing wrong here and if the way I have printing setup would work?

EDIT: Sorry forgot to add the errors here they are

compile error
/rails1/app/views/ordersdisplay.html.erb:22: syntax error, unexpected ':', expecting ')'
...rtotals = Orderlines.where(id: @orderinfo.id).sum("quantity ...
                          ^
/rails1/app/views/ordersdisplay.html.erb:22: syntax error, unexpected ')', expecting   kEND
...lines.where(id: @orderinfo.id).sum("quantity * price")
                          ^
/rails1/app/views/ordersdisplay.html.erb:55: syntax error, unexpected kENSURE, expecting $end