Question

I need to select date and average values from a datacontext’s table and I need to group it by year and by month.
In SQL it will look like this

select Year(data) as years, Month(data) as months, Avg(value) as prices from Prices
group by Year(data),MONTH(data)
order by years, months

I’ve created a LINQ query

var query0 = from c in dc.Prices
             where Convert.ToDateTime(c.data).CompareTo(left) >= 0
                   && Convert.ToDateTime(c.data).CompareTo(right) <= 0
                   && c.idsticker.Equals(x)
              group c by new { ((DateTime)c.data).Year, ((DateTime)c.data).Month }
                    into groupMonthAvg
              select groupMonthAvg;

But I don’t know how to get average values in result

Answer 1

Use the Average function.

var query0 = from c in dc.Prices
             where Convert.ToDateTime(c.data).CompareTo(left) >= 0
                   && Convert.ToDateTime(c.data).CompareTo(right) <= 0
                   && c.idsticker.Equals(x)
              group c by new { ((DateTime)c.data).Year, ((DateTime)c.data).Month }
                    into groupMonthAvg
              select new
              {
                  years = groupMonthAvg.Key.Year,
                  months = groupMonthAvg.Key.Month,
                  prices = groupMonthAvg.Average(x=>x.value)
              };