Question

I have this simple piece of sql that does exactly what I need…

SELECT MIN(pb.Id) AS Id, MIN(pb.Quantity) AS Requested, SUM(pbi.Quantity) AS Total
FROM PickBatchItems AS pb
LEFT JOIN PickBatchItemLocations AS pbi ON pb.Id = pbi.PickBatchItemId
GROUP BY pb.Id

Results in…

Id, Requested, Total
 1    100       NULL
 2    200       165
 3    200       NULL 

This is exactly what I want but I need this to be in Linq.

So far I have…

var pick = (from pb in db.PickItems
           join pbi in db.PickItemLocations on pb.Id equals pbi.PickBatchItemId into TempJoin
           from resList in TempJoin.DefaultIfEmpty()
           where pb.Id == iPickItemId
           group resList by pb.Id into g
           select new
           {
               Id = g.Key,
               RequestedQuantity = g.Min(???????????????????????),
               SentQuantity = g.Sum(a => a.Quantity == null ? 0 : a.Quantity),
           }).FirstOrDefault();

How can I get the RequestedQuantity?

UPDATE:

Thanks to ‘David B’ I have the answer:

var pick = (from pb in db.PickBatchItems
            join pbi in db.PickBatchItemLocations on pb.Id equals pbi.PickBatchItemId into TempJoin
            from resList in TempJoin.DefaultIfEmpty()
            where pb.Id == iPickItemId
            group new { PickItem = pb, PickItemLocation = resList } by pb.Id into g
            select new
            {
                Id = g.Key,
                RequestedQuantity = g.Min(a => a.PickItem.Quantity),
                SentQuantity = g.Sum(a => a.PickItemLocation.Quantity == null ? 0 : a.PickItemLocation.Quantity),
            }).FirstOrDefault();

This joins and returns my two tables even if the PickBatchItemLocations table is empty.

Answer 1

Assuming that PickItems.Id is the primary key, it seems that joining is the first step to a road that need not be traveled.

from pb in db.PickItems
where pb.Id = iPickItemId //this wasn't in the original sql
select new
{
  Id = pb.Id,
  RequestedQuantity = pb.Quantity,
  SentQuantity = pb.PickItemLocations.Sum(pbi => pbi.Quantity)
};

---

If you still want to take the long road, do this:

group new {PickItem = pb, PickItemLocation = resList } by pb.Id into g
select new
{
  Id = g.Key,
  RequestedQuantity = g.Min(x => x.PickItem.Quantity),
  SentQuantity = g.Sum(x => x.PickItemLocation.Quantity ?? 0)
}