Best way to partition in LINQ

Question

Considering a table like this

Id	Date
1	30/07/2022
1	29/07/2022
1	28/07/2022
2	15/07/2022
3	15/07/2022
3	14/07/2022

How do you write a linq query to get this result? (in one query of course, and without any loop)

Id	Date
1	30/07/2022
2	15/07/2022
3	15/07/2022

Or to specify it clearly, the closest date by Id

It's easy to write this in SQL but I can't find a satisfying way to do it in LINQ

Answer 1

var result = table
    .GroupBy(t => t.Id)
    .Select(t => new { Id = t.Key, Date = t.Max(o => o.Date)})
    .ToList();

Answer 2

Thera are the ways that I know, if you need all fields from table, not just Date.

EF 6 and EF Core 6 +

var query = 
    from c in db.Some
    group c by new { c.Id } into g
    select g.OrderByDescending(c => c.Date).First();

Other versions and probaly other providers

// make common variable because it may be query with filter
var data = db.Some;

var query = 
    from d in data.Select(d => new { d.Id }).Distinct()
    from c in data
        .Where(c => c.Id == d.Id)
        .OrderByDescending(c => c.Date)
        .Take(1)
    select c;

Fastest variant via linq2db

var query = 
    from c in db.Some
    select new 
    {
        c,
        RN = Sql.Ext.RowNumber().Over()
            .PartitionBy(c.Id)
            .OrderByDesc(c.Date)
            .ToValue()
    } into s
    where s.RN == 1
    select s.c;