Count Total Using Linq

Question

I have a query like this:

SELECT [degree_id], [institution_id]
FROM [dbo].[instlist]
where [degree_id]=1
group by institution_id, degree_id

I need to count total rows, so I then use a for loop to get count and then return it. How to convert the query above in Linq? Thanks.

[HttpGet]
    public int GetDegreeCountByInstitution(int degreeid)
    {
        var qry = db.instlist
                   .GroupBy(g => new { g.degree_id, g.institution_id })

                  .Select(n => new { degree_id=n.degree_id, institution_id=n.institution_id });



        var cnt=0;
        for( int i=0; i<qry.ToList().Count; i++)
        {
            cnt = cnt + 1;
        }

        return cnt;
    }

There is an error on the select statement.

Answer 1

类似的东西：

var q = (from id in instlist
         where id.degree_id == 1
         select id.degree_id, id.institution_id).Distinct().Count()

Answer 2

您可以对count;

应用group by

   var result = db.instlist.Where(x => x.degree_id == 1)
        .GroupBy(x => new { x.degree_id, x.institution_id })
        .Select(g => new
        {
            degree_id = g.Key.degree_id,
            institution_id = g.Key.institution_id,
            count = g.Count()//Apply count for grouped records
        }).ToList();