1)单个字段Group by:
//a.Key类型与a.Province字段类型一样
.GroupBy(a => a.Province).Select(a => a.Key).ToList();
2)多个字段Group by:
//此时返回的数据列表需要自己转换
.GroupBy(a => new { a.Date, a.Week }).Select(a => a.Key).ToList();
3)单个字段Order by:
.OrderBy(a => a.Date).ToList()
4)多个字段Order by:
.OrderBy(a => a.Date).ThenBy(a => a.EndTime).ThenBy(a => a.StartTime).ToList()
5)多个字段Order by倒序:
.OrderByDescending(a => a.Date).ThenByDescending(a => a.EndTime).ThenByDescending(a => a.StartTime).ToList()