c# - LinqでSum()を使用するにはどうすればよいですか?

Question

このステートメントを LINQ に変換するにはどうすればよいですか?

SELECT Sum(Balance) FROM account WHERE name='stocks' AND userid=290;

Answer 1

decimal sumLineTotal = (from od in account
                        where name == 'stocks' && userid == 290
                        select Balance).Sum();

Answer 2

var sum = db.account.Where(a => a.name == "stocks" && a.userid == 290)
                    .Sum(a => a.Balance);

Answer 3

このような：

myBalanceSum = account.Where(x => x.name == 'stocks' && x.userid == 290 ).Sum(x => x.Balance);