CODEWITHSUNDEEP
c#linqentity-framework
Homam
Homam

Reputation: 23871

How can I get the record which its value is the maximum

I have a table contains a column with Date datatype. I want to get the record which its date value is the maximum.

Linq supports Max, but it returns the value itself. I want the record which its value is the maximum.

Any help!

Upvotes: 0

Views: 116

Answers (4)

Mark Wilkins
Mark Wilkins

Reputation: 41262

Assuming "record" is referring to a record from a table in an underlying database that can handle the resulting SQL efficiently (and supports the max aggregate):

var q = 
    from t in thetable where t.Date == thetable.Max( d => d.Date ) select t;

That would find records matching the maximum date. First() could be used to grab just one.

Upvotes: 0

Geoff Appleford
Geoff Appleford

Reputation: 18832

Assuming Records is a collection of your object and the column/property to get the max of is called value:

var q = Records.OrderByDescending(p => p.value)
               .FirstOrDefault();

Upvotes: 6

Zenuka
Zenuka

Reputation: 3250

You can order the collection by date and select the first one:

List<Record> records = new List<Record>();
records.OrderByDescending(record => record.Date).First();

You could use FirstOrDefault() to not throw an Exception when the collection is empty (null is returned)

Upvotes: 2

Jon Skeet
Jon Skeet

Reputation: 1503924

Unfortunately LINQ doesn't have a MaxBy operator. You probably need to order your items descending by the appropriate property, and then take the first value:

Customer lastRegistered = db.Customers.OrderByDescending(x => x.RegistrationDate)
                                      .FirstOrDefault();

Hopefully SQL Server can work out how to do that without really doing a full sort :)

In LINQ to Objects it's relatively easy to write a MaxBy method of course - I've got on in MoreLINQ for example.

Upvotes: 1

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