Please suggest a linq query for my requirement - linq

Question

Can anyone suggest a linq query for the below requirement.
There is a Checkbox on the form..when we click on it...As per the below datatable it has to be grouped according to ItemCode,Sum(SoldQty), StockInHand,LatestRecordValueOfSales, Amount, Description.
You can't group. the following columns
solddate - show the latest sold date
department
category
ItemCode Description UOM SoldQty Stock in Hand SellPrice Amount
---------------------------------------------------------------
100 Paracetamol 200MG UOM1 5 -5 3 8 0 100 1/21/2013 MEAT INDIAN BEAF
100 Paracetamol 200MG UOM1 5 -5 3 8 0 100 1/21/2013 MEAT INDIAN BEAF
200 frozen meat Kilograms 0.005 88.19 4 4.01 0 200 1/21/2013 OTHERS INDIAN BEAF
200 frozen meat Kilograms 0.044 88.19 4 4.04 0 200 1/21/2013 OTHERS INDIAN BEAF
100 Paracetamol 200MG UOM1 5 -5 3 8 0 100 1/22/2013 MEAT INDIAN BEAF
200 frozen meat Kilograms 0.054 88.19 4 4.05 0 200 1/22/2013 OTHERS INDIAN BEAF
200 frozen meat Kilograms 0.055 88.19 4 4.06 0 200 1/22/2013 OTHERS INDIAN BEAF
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Answer 1

General query
var resQuery = from i in someQueryable
group i by new {i.groupProperty1, i.groupProperty2} into g
select new
{
Property1 = g.Key.Property1,
Property2 = g.Key.Property2
Total = g.Sum(p => p.SumProperty),
/// other properties
};
For your example data it could be like:
var resQuery = from i in dbContext.Items
group i by new{ i.ItemCode, i.Description, i.UOM} into g
select new
{
ItemCode = g.Key.ItemCode,
TotalSold = g.Sum(p => p.SoldQty),
Description = g.Key.Description,
UOM =g.Key.UOM
/// other properties
};
Try example on Ideone: http://ideone.com/xXwgoG
Similar questions asked on SO many times:
Linq Objects Group By & Sum
LINQ Lambda Group By with Sum
Multiple group by and Sum LINQ

Answer 2

Below is my code and it works fine but only for the first row the soldqty and Amount values are getting doubled.while other rows data is fine.I am not able to understand why only the first row data Sum(SoldQty) is getting doubled.
decimal? SoldQty, stockinhand,SellPrice,Amount,CostPrice;
string ItemCode, Description,UOM,BarCode,SoldDate,Department,Category,User;
var resQuery = from row in dtFilter.AsEnumerable()
group row by row.Field<string>("Item Code") into g
select dtFilter.LoadDataRow(new object[]
{
ItemCode=g.Key,
Description=g.Select(r=>r.Field<string>("Description")).First<string>(),
UOM=g.Select(r=>r.Field<string>("UOM")).First<string>(),
SoldQty = g.Sum(r => r.Field<decimal?>("Sold Qty")).Value,
stockinhand=g.Select(r=>r.Field<decimal?>("Stock in Hand")).First<decimal?>(),
SellPrice=g.Select(r=>r.Field<decimal?>("Sell Price")).First<decimal?>(),
Amount = g.Sum(r => r.Field<decimal?>("Amount")).Value,
CostPrice = g.Sum(r => r.Field<decimal?>("Cost Price")).Value,
BarCode=g.Select(r=>r.Field<string>("Barcode")).First<string>(),
SoldDate=g.Select(r=>r.Field<string>("SoldDate")).Last<string>(),
Department=g.Select(r=>r.Field<string>("Department")).First<string>(),
Category=g.Select(r=>r.Field<string>("Category")).First<string>(),
User=g.Select(r=>r.Field<string>("User")).First<string>(), }, false);