如何将此请求转换为LINQ？

Question

• SELECT STEPID，count（）as nb FROM问题GROUP BY StepID ORDER by nb;

Answer 1

你可能应该通过LINQ的基础知识。微软文档有一整个章节专门为LINQ：https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/linq/

如果你在一个被称为类型的questions，列表数据List<Question>，那么你应该能够在您的查询转换是这样的：

var ret = from q in questions 
      group q by q.StepId into grouped 
      let count = grouped.Count() 
      orderby count 
      select new { StepId = grouped.Key, nb = count }; 

Answer 2

查询理解语法：在方法的语法

from q in questions 
group q by q.StepId into g 
select new { StepId = g.Key, Count = g.Count() } into stepCount 
orderby stepCount.Count 
select stepCount; 

完全一样（我比较喜欢的，因为它可以全部查询语法可以加更多，也往往是更紧凑）：

questions 
.GroupBy(q => q.StepId) 
.Select(g => new { StepId = g.Key, Count = g.Count() }) 
.OrderBy(stepCount => stepCount.Count) 

使用另一种过载GroupBy变体：

questions 
.GroupBy(q => q.StepId, (key, values) => new { StepId = key, Count = values.Count() }) 
.OrderBy(stepCount => stepCount.Count);