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GroupBy in subquery with MAX() in C#

I Have this code. It works fine but when I have two same maximal values it appear 2 times. So I need to use OrderBy. But I dont know how. Thanks for any help.
IQueryable<PerformanceRealization> pr = _context.PerformanceRealization
.Where(u => u.Deadline == _context.PerformanceRealization
.Where(x => x.GroupRealizationId == u.GroupRealizationId)
.Max(x => x.Deadline)
)
.Select(u => u);
Here is the SQL code with GROUP BY
SELECT PR.GroupRealizationId
FROM Stores.PerformanceRealization PR
LEFT JOIN Stores.GroupRealization ON Stores.GroupRealization.Id = PR.GroupRealizationId
WHERE PR.Deadline = (SELECT MAX(Deadline)
FROM Stores.PerformanceRealization PR2
WHERE PR.GroupRealizationId = PR2.GroupRealizationId)
GROUP BY PR.GroupRealizationId

You can select the first object from the group
IQueryable<PerformanceRealization> pr2 = pr
.GroupBy(x => x.GroupRealizationId)
.Select(g => g.First());
If you need a specific object from the group, then you can order by another column
IQueryable<PerformanceRealization> pr2 = pr
.GroupBy(x => x.GroupRealizationId)
.Select(g => g.OrderBy(x => x.SomeColumn).First());
for SomeColumn having the smallest value. For the greatest value, use OderByDescending instead.
Of course, you can integrate this approach into the first query:
IQueryable<PerformanceRealization> pr = _context.PerformanceRealization
.Where(u => u.Deadline == _context.PerformanceRealization
.Where(x => x.GroupRealizationId == u.GroupRealizationId)
.Max(x => x.Deadline)
)
.GroupBy(x => x.GroupRealizationId)
.Select(g => g.OrderBy(x => x.SomeColumn).First());
Note, you don't need to have a Select at the end like .Select(u => u). Since it has no effect, you can just drop it.
If your EF Core version cannot handle it (as revealed in a comment), then transition to LINQ-to-Objects with AsEnumerable(), but do the filtering in EF Core to minimize the number of records sent to the front-end:
IQueryable<PerformanceRealization> pr = _context.PerformanceRealization
.Where(u => u.Deadline == _context.PerformanceRealization
.Where(x => x.GroupRealizationId == u.GroupRealizationId)
.Max(x => x.Deadline)
)
.AsEnumerable() // <===== transition from LINQ-to-EF-Core to LINQ-to-Objects
.GroupBy(x => x.GroupRealizationId)
.Select(g => g.OrderBy(x => x.SomeColumn).First());

Queries can't be translated

After migrating to .NET 6 I am receiving following errors.
var subsQuery = context.SubscriptionUsers
.Where(x => subscritpionIds.Contains(x.SubscriptionId));
var subscriptionUsers = await context.Users
.Include(x => x.UserSettings)
.Join(subsQuery, u => u.Id, su => su.UserId, (u, su) => new { su.SubscriptionId, User = u })
.GroupBy(x => x.SubscriptionId)
.ToDictionaryAsync(x => x.Key, x => x.Select(x => x.User).ToList());
This code throws:
The LINQ expression ... could not be translated. Either rewrite the query in a form that can be translated, or switch to client evaluation explicitly by inserting a call to 'AsEnumerable', 'AsAsyncEnumerable', 'ToList', or 'ToListAsync'. See https://go.microsoft.com/fwlink/?linkid=2101038 for more information.
I can't understand why it throws error, but hiding "GroupBy" part - solves it. My solution is this:
var subscriptionUsers = (await context.Users
.Include(x => x.UserSettings)
.Join(subsQuery, u => u.Id, su => su.UserId, (u, su) => new { su.SubscriptionId, User = u })
.ToListAsync())
.GroupBy(x => x.SubscriptionId)
.ToDictionary(x => x.Key, x => x.Select(x => x.User).ToList());
And I have another place, where I get same but different error:
var subscriptionsToSendTo = await context.Subscriptions
.Join(context.PricingPlans.Where(x => x.SystemName == "PromoOneUsd"), sub => sub.PricingPlanId, pp => pp.Id, (sub, pp) => sub)
.Include(x => x.SubscriptionUsers)
.ThenInclude(x => x.User)
.ThenInclude(x => x.UserSettings)
.Where(x =>
(x.EndDate < daysRangeFromNow && x.EndDate > DateTime.UtcNow) &&
(x.SubscriptionUsers.FirstOrDefault()
.User.UserSettings.FirstOrDefault(us =>
us.Name.Equals("ReceivedSevenDaysBeforeNinetyNineCentOfferExpires")
&& us.Value.Equals("true", StringComparison.InvariantCultureIgnoreCase)) == null
)
).ToListAsync();
Which throws:
The LINQ expression ... could not be translated. Additional information: Translation of the 'string.Equals' overload with a 'StringComparison' parameter is not supported. See https://go.microsoft.com/fwlink/?linkid=2129535 for more information. Either rewrite the query in a form that can be translated, or switch to client evaluation explicitly by inserting a call to 'AsEnumerable', 'AsAsyncEnumerable', 'ToList', or 'ToListAsync'. See https://go.microsoft.com/fwlink/?linkid=2101038 for more information.
I fixed this with:
var subscriptionsToSendTo = await context.Subscriptions
.Join(context.PricingPlans.Where(x => x.SystemName == "PromoOneUsd"), sub => sub.PricingPlanId, pp => pp.Id, (sub, pp) => sub)
.Include(x => x.SubscriptionUsers)
.ThenInclude(x => x.User)
.ThenInclude(x => x.UserSettings)
.Where(x =>
(x.EndDate < daysRangeFromNow && x.EndDate > DateTime.UtcNow) &&
(x.SubscriptionUsers.FirstOrDefault()
.User.UserSettings.FirstOrDefault(us =>
us.Name.ToLower() == "receivedsevendaysbeforeninetyninecentofferexpires"
&& us.Value.ToLower() == "true") == null
)
).ToListAsync();
So I have questions:
Why first part throws exception?
Are my solutions alright? Any better solutions?
Regards

Linq: GroupBy not show result for the .Include clause

Why in the result "Titolare" is null?
If I don't use GroupBy, "Titolare" has value.
Thank you.
var ben = context.Benefici.Include("Titolare").Include("Titolare.ComuneDomicilio")
.Where(b => !b.Titolare.SD1_DAT_DECESSO.HasValue)
.OrderByDescending(b => b.SDB_DAT_INIZIO)
.GroupBy(b => b.SDB_CODDIS)
.ToList()
.Select(b => b.First())
.ToList();

It is because of GroupBy limitation - you cannot get grouped items using LINQ to Entities. It should be fixed in EF Core 6.
To get first item of the group, you have to rewrite your query. It is mimic of what will be generated by EF Core 6:
var itemsQuery = context.Benefici
.Where(b => !b.Titolare.SD1_DAT_DECESSO.HasValue);
var benQuery =
from u in itemsQuery.Select(b => new { b.SDB_CODDIS }).Distinct()
join b in itemsQuery
.Include(x => x.Titolare.ComuneDomicilio)
.Where(x => x.SDB_CODDIS == u.SDB_CODDIS)
.OrderByDescending(x => x.SDB_DAT_INIZIO)
.Take(1)
select b;
var ben = benQuery.ToList();

Problem in Search From One List in Another List in Ef .Net Core

List<string> groupId = request.GroupId.Split(',').ToList();
ENTITIES.ProductGroup
.Where(p => p.IsDisplay)
.Where(p => p.FK_GroupNavigation.IsDisplay)
.Where(p => groupId.Any(g => g == (p.FK_Group ?? 0) + "")
.ToList();
The value in request.GroupId is "12,15" and the same values are in the table, but give the following error.
In Ef Core I want to search for some value in another list but it gives the following error What is the problem?
TargetFramework=5.0
The LINQ expression 'DbSet()
.Where(p => p.IsDisplay)
.LeftJoin(
inner: DbSet(),
outerKeySelector: p => EF.Property<Nullable>(p, "FK_Group"),
innerKeySelector: g => EF.Property<Nullable>(g, "PK_Group"),
resultSelector: (o, i) => new TransparentIdentifier<ProductGroup, Group>(
Outer = o,
Inner = i
))
.Where(p => p.Inner.IsDisplay)
.Count(p => __groupId_0
.Any(g => (g ?? "").Equals((object)(p.Outer.FK_Group ?? 0) + "")))' could not be translated. Either rewrite the query in a form that can be translated, or switch to client evaluation explicitly by inserting a call to 'AsEnumerable', 'AsAsyncEnumerable', 'ToList', or 'ToListAsync'.

Any with local collection is not translatable to SQL, use Contains instead. Also compare integers by integer values, query will use indexes if they are exists.
List<int> groupId = request.GroupId.Split(',').Slect(s => int.Parse(s)).ToList();
SGP_PRODUCT.ProductGroup
.Where(p => p.IsDisplay)
.Where(p => p.FK_GroupNavigation.IsDisplay)
.Where(p => groupId.Contains(p.FK_Group))
.ToList();

EF 6 complex query with Include not including relations

i have a somewhat complex structure i wont get into,
but what i try doing is:
Get all ShopItems, who's SourceItem has changed,
Get and update them according to their Source/Shop data.
i conjured the following:
var query = _ctx.ShopItems
.Include(si => si.Shop)
.Include(si=>si.SourceItem)
.Include(si => si.SourceItem.Source)
.Include(si=>si.Shop.ShopType)
.GroupBy(i => i.SourceItem)
.Where(g => g.Key.LastUpdate > lastUpdate)
.OrderBy(g => g.Key.LastUpdate)
.Take(updateCountLimit);
the query seems to work, but when itterating the Groups:
groupItem.Key.Source is null.
I somewhat solved it by Removing the Include()s, saving the Entities to an Array, and explicitly loading the references using
_ctx.Entry(updatedSourceItem.Key).Reference(src=>src.Source).Load();
How can i perform the query i want without round-tripping the DB for explicit loading ?

Not sure, but it's backwards to start with ShopItems and then group by SourceItem. Try just starting with SourceItem, something like
:
var query = _ctx.SourceItems
.Include(i => i.ShopItems)
.Include(i => i.Source)
.Include(i => i.ShopItems.Select( si => si.Shop))
.Include(i => i.ShopItems.Select( si => si.Shop).ShopType)
.Where(i => i.LastUpdate > lastUpdate)
.OrderBy(i => i.LastUpdate)
.Take(updateCountLimit);
//or
var query = _ctx.SourceItems
.Include("ShopItems")
.Include("Source")
.Include("ShopItems.Shops")
.Include("ShopItems.Shops.ShopType")
.Where(i => i.LastUpdate > lastUpdate)
.OrderBy(i => i.LastUpdate)
.Take(updateCountLimit);