如何使用多列对数据进行分组 [英] How do I group data using multiple columns

问题描述

我无法对从数据库中检索到的数据进行分组，该数据由于具有我不需要的数据的列而具有重复。我试图使用distinct或group by来摆脱裁员。

I am having trouble grouping a data retrieved from database which has duplication due to a column with data i don't need. i was trying to use distinct or group by to get rid of the redundancies.

var students= db.student.Distinct().Where(c => c.classdate== tomorrow || c.classdate== todayd).ToList();

它将返回学生的姓名，但也会根据当天的课程重复学生记录。我只想获得今天和明天上课的学生名单。



我尝试过的事情：



我累了

it will return student's name but also duplicates student record according to course available on that day. I just wanted to get list of students who has class today and tomorrow.

What I have tried:

I have tired

students.GroupBy(x => new { x.Fn  ame, x.classdate});

推荐答案

试试这个：

Try this:

var students= db.student
    .Where(c => c.classdate== tomorrow || c.classdate== todayd)
    .Select(c.studentname)
    .Distinct()
    .ToList();

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