Convert SQL into Linq query

Question

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

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);

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.

Can anyone help me with this?

score 15 · Answer 1 · answered May 16 '13 at 07:13

15

var query = from row in db.Person
            where row.EnrollmentDate != null
            group row by row.EnrollmentDate into grp
            select new {
                EnrollmentDate = grp.Key,
                Count = grp.Count()
            };

answered May 16 '13 at 07:13

Marc Gravell

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thats cool!!! @Marc Gravell, thnx for ur answer, but i was looking for Linq in lamda expression as Habib's answer. but anyways thanx 4 a quick reply – Ashok Damani May 16 '13 at 07:33

score 11 · Accepted Answer · edited May 16 '13 at 07:13

11

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

edited May 16 '13 at 07:13

Mahmoud Gamal

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answered May 16 '13 at 07:12

Habib

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thanx for ur answer, but i am getting an `error(xyzModel.SchoolContext does not contain any defenition for Person)` the ques has been updated... plz see it again. thanx – Ashok Damani May 16 '13 at 07:29
@ashok_damani, what is the class representing your table `Person` in your model ? Replace that in your query – Habib May 16 '13 at 07:30
ur answer edited, now its working fine. but one more thing, i m writing here `Select( group=> new EnrollmentDateGroup()`, but as previous i tried it to convert into the `List` (by adding `ToList()` at tail), but didnt worked, Y ? – Ashok Damani May 16 '13 at 07:57
@ashok_damani, I can't see your edit, but for your answer of converting it to `List` is not allowed since you are selecting an [anonymous object](http://msdn.microsoft.com/en-us/library/vstudio/bb397696.aspx) using `new` keyword – Habib May 16 '13 at 07:59

Convert SQL into Linq query

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