Given a simple schema e.g. PurchaseOrders { OrderId, Total, LineItemCount }, I want to generate a simple query for some simple stats like below:
select sum(lineitemcount) as totalitems, sum(total) as totalsales
from purchaseorders
However in Linq to Sql I am struggling to get this into one query.
At the moment I have this:
decimal totalSales = PurchaseOrders.Sum(po => po.Total)
decimal totalItems = PurchaseOrders.Sum(po => po.LineItemcount)
Is there a way to do this as one query?
Closest I can work out is to give it a fake group-by clause. It works, and outputs as you'd expect, but the generated SQL actually winds up passing in a parameter of "1" and grouping on it which is a tad suboptimal. Here's the syntax for what I've got though:
PurchaseOrders
.GroupBy(po => 1)
.Select(pogroup => new {
TotalSales = pogroup.Sum(po => po.Total),
TotalItems = pogroup.Sum(po => po.LineItemCount)
});
Maybe you can try Aggregate:
var totOrder= PurchaseOrders.Aggregate((preOrder, thisOrder)=>SumTwoOrder(preOrder, thisOrder));
var totalSales = totOrder.Total;
var totalItems=totOrder.LineItemCount;
This is how you can define the SumTwoOrder method:
public PurchaseOrder SumTwoOrder(PurchaseOrder prev, PurchaseOrder thisOrder)
{
return new PurchaseORder(prev.Total+thisOrder.Total, prev.LineItemCount+thisOrder.LineItemCount);
}
Here is one way that should work. I'm not sure of the data types so I assumed nullable integers.
from t in (
from t in PurchaseOrders
select new {
t.LineItemCount,
t.Total,
Dummy = "x"
}
)
group t by new { t.Dummy } into g
select new {
TotalItems = (System.Int32?)g.Sum(p => p.LineItemCount),
TotalSales = (System.Int32?)g.Sum(p => p.Total)
}
