select, group, sum with ASP LINQ + private compare method - sql

Question

i am working on an ASP MVC Project and i have a part where i need to export some data to an excel file. the thing is that i need to sum some rows to display a single row. I am not familiar with sql or linq and i am struggling to get the result i want.
there should be 4 columns: requester(string), date(datetime), collection(string), timeinvested(int).
the grouping should be by the column 'collection' (string) as default and if the filter input for requester or date was filled than that would be the next level of grouping. the column 'timespent' should be summarized by the result of the grouping.
example:
requester, date, collection, timeinvested
(1) john, jan 1st, 2019, collection1, 1
(2) mike, jan 1st, 2019, collection1, 3
(3) eric, jan 1st, 2019, collection1, 2
(4) july, jan 1st, 2019, collection2, 5
(5) john, jan 1st, 2012, collection1, 3
here we have 5 rows from the table, once we filter to export only by default (column collection) then rows 1+2+3+5 should sum to 1 row and the 2nd row will be row 4, because the collections are different. like so:
requester, date, collection, timeinvested
(1) john, jan 1st, 2019, collection1, 9
(2) july, jan 1st, 2019, collection2, 5
if i choose to filter also by requester or date then it should apply accordingly.
one big thing here is that there is a private method that checks the date to a particular date and it should export to the file the date year if its after or before the checked date. for example: relative date dec 1st of the same year
if the row date is before relative date then we should write date year - 1;
thanks
var q = (from a in items
select new {
Requester = a.Requester.Name,
Collection = a.Collection.Name,
TimeSpent = a.TimeSpent,
Year = a.Date,
})
.ToList()
.GroupBy(x => new {
x.Requester,
x.Collection,
x.Year,
x.TimeSpent
})
.Select(y => new CollectionModel {
Requester = y.Key.Requester,
Collection = y.Key.Collection,
TimeSpent = y.Sum(z => Convert.ToInt32(z.TimeSpent)),
Year = checkDate(y.Key.Year),
});
return q.ToList();
this is how i made it work:
var q = (from a in items
select new {
Requester = a.Requester.Name,
Collection = a.Collection.Name,
TimeSpent = a.TimeSpent,
Year = a.Date,
})
.Where(Where(a => dt == null || (dt != null && a.Year == dt.Year))
.ToList()
.GroupBy(x => new {
x.Requester,
x.Collection,
x.Year,
})
.Select(y => new CollectionModel {
Requester = y.Key.Requester,
Collection = y.Key.Collection,
TimeSpent = y.Sum(z => Convert.ToInt32(z.TimeSpent)),
Year = checkDate(y.Key.Year),
});
return q.ToList();

Answer 1

First, remove the "x.TimeSpent" from your GroupBy, you need to aggregate that variable, not group by it. secondly, could you post the output as well?