如何使用取决于日期的价格总和进行实体框架查询？

Question

Hello StackOverflow community,

I have a question,

I want to create a query which is able to do the some of all price (which is a double), depends of the date.

--SQL Query
  select sum(price) from dbo.contracts where create_date ='2009-01-01' group by (id);

I tried this Linq query but it didn't worked:

--Linq Query
public static double getPriceFromMonth(int year, int month)
 {
    return unitOfWork.Contracts.GetAll().Where(c => c.create_date.Year == year && c.create_date.Month == month).GroupBy(c => c.id).Select(s => new { total = s.Sum(c => c.price) });
 }

I hope this isn't too complicated ^^'

Answer 1

Try:

unitOfWork.Contracts.GetAll()
    .Where(c => c.create_date.Year == year && c.create_date.Month == month)
    .Sum(c => c.price);