1简单方式
var query=db.StudentScore.Where(r=> r.SubjectId==subjectId).Select(g=>g).ToList();
var query=db.StudentScore.Where(r=> r.SubjectId==subjectId).Select(g=>g
).ToList();
2 var query=db.StudentScore.Where(r=> r.SubjectId==subjectId).Select(g=>new{d.SelectId, d.想要的字段}).ToList();
var query=db.StudentScore.Where(r=> r.SubjectId==subjectId).Select(g=>new{d.SelectId, d.想要的字段}