CODEWITHSUNDEEP
c#linq
user3635120
user3635120

Reputation: 73

How to select Max StartDate in Linq

I want to only get out the max StartDate, its multiples of dates with the same CustomNumber

Any suggestions?

My simplified code

from Cus in Customers
where Cus.CustomNumber == 2 
group Cus by new 
 { Cus.Name,Cus.City,Cus.StartDate}
 into grp
 select new 
 {
    Name = grp.Key.Name,
    City = grp.Key.City, 
    StartDate = grp.Key.StartDate,

    //I have tried, but it doesnt work for me
    //StartDate = grp.Max(Cus=> grp.Key.StartDate)
 }

Upvotes: 1

Views: 93

Answers (2)

Christos
Christos

Reputation: 53958

You could try this one:

var result = from Cus in Customers
             where Cus.CustomNumber == 2 
             group Cus by new 
             { Cus.Name, Cus.StartDate}
             into grp
             select new 
             {
                 Name = grp.Key.Name,
                 StartDate = grp.Max(x=>x.StartDate)
             };

Using grp you have access to the random group you create in your linq query, then using the extension method called Max you get the maximum StartDate in your group.

UPDATE

Since now you have a join before the grouping, you have to change your code to the following one:

var result = from res in 
             (from customer in Customers
             join house in Houses 
             on customer.CustomNumber equals house.CustomNumber
             where customer.CustomNumber == 2               
             select new { Name = customer.Name, StartDate = house.StartDate })
             group res by res.Name into grp
             select new { Name = grp.Key, StartDate = grp.Max(x=>x.StartDate) };

UPDATE #2

If you want you get both the customer's Name and City in your result, you have to use the following code:

var result = from res in 
             (from customer in Customers
             join house in Houses 
             on customer.CustomNumber equals house.CustomNumber
             where customer.CustomNumber == 2               
             select new { Name = customer.Name, City = customer.Name, StartDate = house.StartDate })
             group res by new { res.Name, res.City } into grp
             select new 
             { 
                 Name = grp.Key.Name, 
                 City = grp.Key.City,  
                 StartDate = grp.Max(x=>x.StartDate) 
             };

Upvotes: 1

Neel
Neel

Reputation: 11721

try below code

StartDate = grp.Max(x => x.StartDate)

Upvotes: 1

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