如何在c#中将特定条件的项目添加到sql中添加特定条件的项后对sql进行分组

这似乎是一个愚蠢的问题，但我确实需要帮助.我不常发问题，但是这次我真的帮了忙.

This might seem like a stupid question but i really need help. I don't often post question but this time i really help.

我需要一个对多个列进行分组的linq to sql查询.不仅如此，其中一列具有特定意义，也需要基于certain condition进行分组.

I need to have a linq to sql query that groups multiple columns. But not just that, one of the columns have specific that also need to be grouped base on certain condition.

我要查询的就是这个.

using (var donnée = new ClassDonnéeDataContext(mycontrng))
        {
            var don = from d in donnée.Reservations
                      where (d.Date_Livraison.Value.Date == startDate.Value.Date) && d.Sortie_Cuisine != "Oui" && d.Livraison != "Annulée" && (d.Reserv_Boutique == "Non" || d.Reserv_Boutique == null)
                      group d by new
                      {
                          Gateau = d.Gateau,
                          Heure = d.Heure_Livraison,
                          Nb_Part = d.Part,
                      } into grs
                      select new
                      {
                          Gateau = grs.Key.Gateau,
                          Heure = grs.Key.Heure,
                          Nombre = grs.Sum(x => x.Nombre),
                          Nb_Part = grs.Key.Nb_Part,
                      };

            var order = from ord in don
                        orderby ord.Heure ascending
                        select ord;

            dgv.DataSource = order;
        } 

我正在寻找的结果是将"Heure_Livraison"列按特定的首字母缩写进行分组.

The result i'm looking for is to have The columns "Heure_Livraison" to be grouped by specific critiria.

查询结果如下.

Gateau:                               Heure:                 Nombre:                  Nb_Part:

Foret Noire                           10                     2                        6
Ganache                               10                     2                        6
Foret Noire                           11                     2                        6
Ganache                               11                     2                        6
Ganache                               12                     1                        6

现在，我想添加所有具有相同名称，相同Nb_Part的蛋糕Between 10-12.所以结果将是

Now i want to add all the Cake of the same name, same Nb_Part Between 10-12. So the result Will like

Gateau:                               Heure:                 Nombre:                  Nb_Part:

Foret Noire                           10                     4                        6
Ganache                               10                     5                        6

如果有人对这个问题有建议，请给我!!!!!!

Please if anyone has a suggestion to this question, give it to me !!!``