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Filtering CosmosDb using LINQ Query; .Contains or .Any LINQ causing exception

I am using CosmosDB and what to load filtered data. I want to do the filtering on the database side but I had some problems, which I think I managed to resolve but not sure why one way works but not another.
I have a list of CarPositions
// I fill this list from cosmosdb data
var carPosition = new List<CarPositions>()
My goal is to only get the cars if I have their positions in the carPosition list
I tried to do something like this
var iterator = CarContainer
.GetItemLinqQueryable<Car>(true)
.Where(x => carPosition.Any(cp => cp.Id == x.Id))
.ToFeedIterator();
Which throws an exception; "Input is not of type IDocumentQuery"
From what I understood from looking online is that CosmosDb provider does not support ANY linq when translating the query to SQL
This then lead me to try doing the same thing but with using Select and Contain
1)
var iterator = CarContainer
.GetItemLinqQueryable<Car>(true)
.Where(x => carPosition.Select(cp => cp.Id).ToList().Contain(x.Id))
.ToFeedIterator();
Again causing the same exception
I then tried this which works but to me this is doing the exact same thing
2)
var carPosIds = carPosition.Select(cp => cp.Id).ToList();
var iterator = CarContainer
.GetItemLinqQueryable<Car>(true)
.Where(x => carPosIds.Contain(x.Id))
.ToFeedIterator();
Can someone explain why the second one works but not the first? Also why the Any linq did not work?

Because the linq statement needs to be translated into a sql query which will run on the database server. The Contains statement inside the Where statement is supported because the SDK has implemented a translation using the sql IN clause (presumably).
While your Any query seems the same, just imagine it being a different expression and how difficult (or nearly impossible) it would become to translate it into an SQL query as the expression grows more complex. E.g. .Any(cp => cp.Id * 2 - x.Id / 2 == x.Id).
If this would be pure C# code running in memory instead of being translated by the SDK into a query for Cosmos all above methods would work (some better than others).

EF Core query where Were clause is a collection?

I am trying to build a sane query in EF Core that returns a collection of things that are, in turn derived from a collection of things. Basically in raw SQL one would do a JOIN.
Its in ASP.NET Core so the initial collection is the list of Roles on the SecurityPrincipal object:
var roles = User.FindAll(ClaimTypes.Role).Select(r=>r.Value);
These roles are then mapped to Groups in our Database, so I can look those up:
var groupsQuery = dbContext.Groups.Where(g=>roles.Any(r=>r==g.GroupName));
var groups = await groupsQuery.ToListAsync();
This query is quite happy and returns a collection of groups as expected. The groups however have access to another resource, which is what I really want and because its a many to many relationship there is a bridging table.
This is me trying to query the AssetGroup joining table so I can get all the Assets referenced by all the Groups that map to a Role on the SecurityPrincipal.
var assetGroupsQuery = dbContext.AssetsGroups.Where(ag => groupsQuery.Any(ag => ag.Id == a.GroupId));
var assetGroups = await assetGroupsQuery.ToListAsync();
When I perform the second query I get a lot of spam in my output window:
The LINQ expression 'where ([ag].Id == [ag].GroupId)' could not be translated and will be evaluated locally.
The LINQ expression 'Any()' could not be translated and will be evaluated locally.
The LINQ expression 'where {from Group g in __groups_0 where ([ag].Id == [ag].GroupId) select [ag] => Any()}' could not be translated and will be evaluated locally.
The LINQ expression 'where ([ag].Id == [ag].GroupId)' could not be translated and will be evaluated locally.
The LINQ expression 'Any()' could not be translated and will be evaluated locally.
Any clues on how one should phrase a nested query like this so EF Core can compose a single SQL query properly?

In general avoid using Any or any LINQ operator other than Contains on in memory collection like your roles (which according to the code should be of type IEnumerable<string>).
In other words, instead of
.Where(g => roles.Any(r => r == g.GroupName))
use the functionally equivalent
.Where(g => roles.Contains(g.GroupName))
The later is guaranteed to be translated to SQL IN, while the former isn't.
Interestingly and at the same time misleading is that EF Core tries to be smart and translate the former the same way as Contains, and succeeds when the containing query is executed, but not when used as part of another query.
It could be considered a current EF Core implementation defect. But the workaround/solution is (as mentioned in the beginning) to not rely on it and always use Contains.

Expressions in Linq Query

I recently found out that i cannot call any methods from within a linq query. I am trying to write a query that, on the where clause compares two byte arrays. The value on the database is a GUID of type Raw(32) and it is returned as a byte array. This is the record ID for this table. I need to compare it to another byte array. the second byte array could be converted to a string but since i cannot call methods from within linq i was unable to compare.
I tied a custom "Compare" method, i also wrote an extension method. All received an error indicating "LINQ to Entities does not recognize the method"
Here is the code for what i am trying to do. The where clause causes this error:
LINQ to Entities does not recognize the method 'Boolean SequenceEqual[Byte] (System.Collections.Generic.IEnumerable1[System.Byte], System.Collections.Generic.IEnumerable1[System.Byte])' method, and this method cannot be translated into a store expression."
EPSGEntities dbContex = new EPSGEntities();
byte[] byteArray = ParseHex(ViewState["itemID"].ToString());
var q = (from d in dbContex.EPSG_VSOREJECTS
where d.SDSRECID.SequenceEqual(byteArray)
select d).First();

What version of EntityFramework are you using? On EF6 I am able to simply do the following against a SQL 2012 table with a varbinary column:
var q = dbContext.EPSG_VSOREJECTS.FirstOrDefault(e => e.SDSRECID == byteArray);
Is the SDSRECID property on EPSGEntities of type byte[]?
The alternative here would be to go to straight Sql to get your object. Something like:
dbContext.Database.SqlQuery<EPSG_VSOREJECT>("SELECT TOP 1 *" +
"FROM dbo.EPSGEntities" +
"WHERE SDSRECID = #byteString",
new SqlParameter
{
ParameterName = "byteString",
Value = ViewState["itemID"].ToString(),
}).FirstOrDefault();
Linq to Entities in EF is awesome for most queries, but I sometimes drop into sql when I need to do something unsupported, complex, or just fast. Hope this helps!

I'm not entirely sure this works, but I've found calling .AsEnumerable() on the IQueryable object set lets me apply pretty much any code I wish:
var q = dbContex.EPSG_VSOREJECTS.
.AsEnumerable()
.Where(d => d.SDSRECID.SequenceEqual(byteArray));
Doing so seems to prevent EF from trying to translate the Where() clause into SQL syntax, but I have no real idea what the performance hit would/will be.
This is also using method syntax, since I'm not real familiar with query syntax. HTH.
EDIT:
As some others have noted, you have to be careful with how you add any of the iterative methods (AsEnumerable(), ToList(), etc.) since past that point you are no longer building SQL against your data store. Once you start iterating, EF will execute whatever query has been built up to that point, and from then on you are filtering the result set from the LINQ query.
In this case, I don't know that this can be avoided, unless someone can build the same query as a sproc (which EF can execute on your behalf).

"Unable to create a constant value of type." How to avoid this error in LINQ query?

I have this method:
public virtual IEnumerable<Invoice> GetHomePageInvoices(IList<Area> areas, FinancialYearLookup financialYear)
{
var homePageInvoices = _db.Invoices.Where(x => areas.Any(z => z.Id == 3)).ToList();
...
}
Basically I'm trying to find any invoices where the area matches with any of those in the parameter area.
I'm getting the error:
Unable to create a constant value of type 'Models.Area'. Only
primitive types ('such as Int32, String, and Guid') are supported in
this context.
Can anyone explain why this is happening and how to fix?

You cannot use an IList<Area> in the context of your Linq Provider (presumably Linq to Entities) - just extract the id's beforehand and use a Contains query which does work on a collection of primitives:
List<int> ids = areas.Select( x=> x.Id).ToList();
var homePageInvoices = _db.Invoices
.Where(x => ids.Contains(x.Id))
.ToList();
Also I assume you did not want to compare with a fixed value of 3 - so I changed your query accordingly - provided the Invoice entity has an Id property.

a. It looks like you have a typo here:
z => z.Id == 3
but the main problem is
b. I'm guessing you're using Linq to Entities but its not clear. In any case what is happening is that the query builder is trying to turn that 'areas.Any(...)' into SQL and it can't do it because areas is not an IQueryable from your database, but a local variable. I suggest you use something like this WhereIn custom Linq operator as described here or here. That will build a SQL in clause containing all the items in areas that you might want to match against.

slightly complex many-to-many linq query got me stuck

So I'm on Linq-To-Entities with an asp.net mvc project.
I always get a little stumped with this sort of query.
My schema is:
ProductTag
+TagName
+<<ProductNames>>//Many-to-many relationship
ProductName
+FullName
+<<Tag>>//Many-to-many relationship
PurchaseRecord
+Amount
+<<ProductName>>//one productname can be linked to Many purchase records.
I need to get the sum of all purchases for a given tag.
This is what I've tried.
ProductTag thetag//could be some tag
decimal total = myentities.PurchaseRecords
.Where(x => thetag.ProductNames.Any
(a => a.FullName == x.ProductName.FullName))
.Sum(s => s.Amount);
I've tried changing a couple of things, tried using Contains, but I know I'm fundamentally wrong somewhere.
I keep getting :
Unable to create a constant value of type 'ProductName'. Only primitive types ('such as Int32, String, and Guid') are supported in this context.
Update
So with #Alexandre Brisebois's help below it worked simply like this:
var total= item.ProductNames.SelectMany(x => x.PurchaseRecords)
.Sum(s => s.Amount);

When you get this sort of error, you need to do all evaluations outside of the linq query and pass the values in as variables.
the problem with your query is that thetag.ProductNames.Any() is out of context.
This evaluation is not converted to SQL since it is not a string/guid or int.
You will need to query for this object within your query and evaluate from this object.
I'm not sure if that was clear.
You would need to do something like
var query1 = (from x in tags where x.tagID = id select x.ProductNames)
.SelectMany(...)
The select many is because you are selecting a collection ProductNames and need to bring it back as a flat set/collection fo that you can do a .Any() on it in the next query.
Then use this and do an query1.Any(logic)
decimal total = myentities.PurchaseRecords.
Where(x => query1.Any
(a => a.FullName == x.ProductName.FullName))
.Sum(s => s.Amount);
By doing this you will stay in linq to entity and not convert to linq to objects.
The ForEach is not an option since this will iterate over the collection.

you can use AsEnumerable method to perform certain portions of query in C# rather than on sql server. this is usually required when you have part of data in memory (Collection of objects) so using them in query is not easy. you have to perform part of query execution on .net side. for your problem plz try
decimal total = myentities.PurchaseRecords.AsEnumerable()
.Where(x => thetag.ProductNames.Any
(a => a.FullName == x.ProductName.FullName))
.Sum(s => s.Amount);
plz visit this link to find more about AsEnumerable