c# – 将SQL转换为Linq查询

我对 Linq查询很新,我只想将我的数据库查询转换为Linq.

这是我简单的SQL查询：

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

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

它运行正常,但是怎么可能在Linq中编写这个查询,我只是无法将group by语句转换为Linq.转换成Linq似乎有些棘手.

谁能帮我这个？

解决方法

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