c# - Linq Getting Customers 按日期分组，然后按类型分组

Question

我正在使用 C# 中的 LINQ 生成报告以向客户展示。我想显示没有。每种类型的客户。

注册的客户有客人和经理三种类型。我想按客户注册日期分组，然后按客户类型分组。即，如果今天插入了 3 位客人、4 位注册人和 2 位经理。明天 4,5 和 6 分别注册。然后报告应显示当天注册的客户数量。每种类型单独一行。

DATE        TYPEOF CUSTOMER    COUNT
31-10-2013  GUEST              3
31-10-2013  REGISTERED         4
31-10-2013  MANAGER            2
30-10-2013  GUEST              5
30-10-2013  REGISTERED         10
30-10-2013  MANAGER            3

像这样。

var subquery = from eat in _customerRepo.Table
                           group eat by new { yy = eat.CreatedOnUTC.Value.Year, mm = eat.CreatedOnUTC.Value.Month, dd = eat.CreatedOnUTC.Value.Day } into g
                           select new { Id = g.Min(x => x.Id) };




var query = from c in _customerRepo.Table
                        join cin in subquery.Distinct() on c.Id equals cin.Id
                        select c;

通过上面的查询，我得到了当天注册的最低客户数提前致谢

Answer 1

var query = _customerRepo.Table
     .GroupBy(c => new {Date = c.Date.Date,  Type = c.TypeOfCustomer})
     .Select(g => new 
                   {
                       Date = g.Key.Date,
                       Type = g.Key.Type, 
                       Count = g.Count
                   }
            )
     .OrderByDescending (r = r.Date);