c# - linq 分组两次

Question

我们有一项调查。我有一个模型如下:

Survey
    City 
    Satisfaction
    Id

Satisfaction 是一个枚举如下:

Satisfaction: 
    VerySatisfied, 
    Satisfied
    Undecided, 
    NotSatisfied

我有兴趣按城市分组，然后我想按 VerySatisfied 和 satisfied 分组。

 var result= _db.Surveys.AsNoTracking()
    .GroupBy(x => x.City)
    .Select(group => new { 
        City = group.Key.Code, 
        CityName = group.Key.Name, 
        Count = group.Count() 
     })
    .OrderByDescending(x => x.Count);

我可以按城市分组，但我需要找到城市内的满意度。

即:纽约:%90%。

如何按两次分组得到上面的结果？

Answer 1

你可以试试这个:

var result= _db.Surveys.AsNoTracking()
               .GroupBy(x => x.City)
               .Select(group => new 
                      {
                            City = group.Key.Code, 
                            CityName = group.Key.Name, 
                            Count = group.Count(),
                            SatisfactionRatio = (group.Count(y => y.Satisfaction == Satisfaction.VerySatisfied || y.Satisfaction == Satisfaction.Satisfied) * 100) / group.Count()
                      })
               .OrderByDescending(x => x.Count);