Query Datatable

Question

I have a DataTable that looks like this:

Id Value
123 4.0
123 5.0
234 1.0
345 2.0
345 3.0

I want to end up with (probably a new DataTable) that contains the sum of values grouped by Id like this:

Id SumOfValue
123 9.0
234 1.0
345 5.0

Here is my code,

var query = from row in dTable.AsEnumerable()
group row by row.Field<double>("ITEM_NO") into grp
orderby grp.Key
select new
{
    ITEM_NO = grp.Key,
    sum = grp.Sum(r = r.Field<double>("ITEM_STOCK"))
};

I am getting an error that r is undefined, also I am not able to add these values in a new datatable.

Does anyone know how to write this?

Thanks.

Answer 1

I believe you are not specifying the operation correctly. Try this:

var query = from row in dTable.AsEnumerable()
                    group row by row.Field<double>("ITEM_NO") into grp
                    orderby grp.Key
                    select new
                    {
                        ITEM_NO = grp.Key,
                        sum = grp.Sum(r => r.Field<double>("ITEM_STOCK"))
                    };

The difference is r => r.Field instead of r = r.Field.