将SQL转换为Linq查询 [英] Convert SQL into Linq query

问题描述

我对Linq查询非常陌生，我只想将数据库查询转换为Linq.

I'm quite new at Linq queries, I just want to convert my DB query into Linq.

这是我简单的SQL查询:

Here is my simple SQL query:

var query = "SELECT EnrollmentDate, COUNT(*) AS StudentCount "
          + "FROM Person "
          + "WHERE EnrollmentDate IS NOT NULL "
          + "GROUP BY EnrollmentDate";

var data = db.Database.SqlQuery<EnrollmentDateGroup>(query);

工作正常，但是如何用Linq编写此查询，我只是不能将group by语句转换为Linq.转换为Linq似乎有些棘手.

It is working fine , but how could it possible to write this query in Linq, I just can't convert the group by statement into Linq. It seems somewhat tricky to convert into Linq.

有人可以帮我吗?

推荐答案

var result = db.Person
               .Where(r=> r.EnrollmentDate != null)
               .GroupBy(r=> r.EnrollmentDate)
               .Select( group=> new 
                              {
                                 EnrollmentDate = group.Key, 
                                 Count = group.Count()
                               });

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