{$unwind:{
path:"$items.item",
preserveNullAndEmptyArrays:true
}},
{
$lookup: {
from: "Parts",
localField: "items.partNumber",
foreignField: "pno",
as: "partsDetails"
}
},
After you can group this.
Ok got this as:
var query = (from t in Transactions
group t by new {t.MaterialID, t.ProductID}
into grp
select new
{
grp.Key.MaterialID,
grp.Key.ProductID,
Quantity = grp.Sum(t => t.Quantity)
}).ToList();
