Linq Query,搞砸了方法中的where子句

Question

我有一个查询,应该返回当前报告的总小时数.下面的代码返回正确的小时总数,但不是数据库中特定用户的小时数.

    public int reportedWeekTime(int currentWeek, string username)
        {
            var totalTime = (from u in context.Users
                         from r in context.Reports
                         from w in context.Weeks
                         from d in context.Days
                         where u.Id == r.UserId && r.weekNr.Equals(currentWeek) && r.Id   == w.ReportId && w.DayId == d.Id
                         select d.Hour).DefaultIfEmpty(0).Sum();
            return totalTime;
        }

第一种方法返回数字24,这是正确的,但正如我所说,不是针对特定用户.

我试图这样做,但它给了我0作为回报.我究竟做错了什么？

    public int reportedWeekTime(int currentWeek, string username)
        {
            var totalTime = (from u in context.Users
                         from r in context.Reports
                         from w in context.Weeks
                         from d in context.Days
                         where u.Id == r.UserId && r.weekNr.Equals(currentWeek) && r.Id == w.ReportId && w.DayId == d.Id && u.Username.Contains(username)
                         select d.Hour).DefaultIfEmpty(0).Sum();
            return totalTime;
        }

Answer 1

更新- 故障排除方法，使用 u.Username 属性、字符串用户名和比较创建一个新的匿名类。更容易想象正在发生的事情

var users = (from u in context.Users
             select new
             { 
               UsernameDb = u.Username,
               UsernameSearch = username,
               Comparison = u.Username.Contains(username),
             }).ToList();

原来的

我会稍微修改你的查询：

1. 在子句中使用join's 代替from'swhere
2. 去除DefaultIfEmpty(0)

（1）更多的是为了可读性，但我认为（2）是你的问题的原因

var totalTime = (from u in context.Users
                 join r in context.Reports on u.Id equals r.UserId
                 join w in context.Weeks on r.Id equals w.ReportId
                 join d in context.Days on w.DayId equals d.Id
                 where r.weekNr.Equals(currentWeek) && u.Username.Contains(username)
                 select d.Hour).Sum();

我还要确保以下查询返回结果。如果没有，那就是你的问题

var users = from u in context.Users
            where u.Username.Contains(username)
            select u;