Where EF6 doing where clause at SQL or at client - sql-server

Question

I am trying to start using EF6 for a project. My database is already filled with millions of records.
I can't find right explanation how does EF send T-SQL to SQL Server? I am afraid that I am going to download bunch of data to user for no reason.
In code below I have found three way to get my data to List<> but I am not sure which is right way to do WHERE clause at SQL.
I do not want to fill client with millions of record and to query (filter) that data at client.
using (rgtBaza baza = new rgtBaza())
{
var t = baza.Database.SqlQuery<CJE_DOC>("select * from cje_doc where datum between #od and #do",new SqlParameter("od", this.dateTimePickerOD.Value.Date ) ,new SqlParameter("do", this.dateTimePickerOD.Value.Date)).ToList();
var t = baza.CJE_DOC.Where(s => s.DATUM.Value >= this.dateTimePickerOD.Value.Date && s.DATUM.Value <= this.dateTimePickerDO.Value.Date).ToList();
var query = from b in baza.CJE_DOC
where b.DATUM >= this.dateTimePickerOD.Value.Date && b.DATUM.Value <= this.dateTimePickerDO.Value.Date
select b;
var t = query.ToList();
this.dataGridViewCJENICI.DataSource = t;
}

Answer 1

In all 3 cases, the filtering will happen on the database side, the filtering (or WHERE clause) will not take place on the client side.
If you want to verify that this is true, especially for your last 2 options, add some logging so that you can see the generated SQL:
baza.Database.Log = s => Console.WriteLine(s);
In this case, since you are using EF already, choose the 2nd or 3rd options, they are both equivalent with different syntax. Pick your favorite syntax.

Answer 2

In all of those examples, EF6 will generate a SQL query including the where clause - it won't perform the where clause on the client.
It won't actually retrieve any data from the database until you iterate through the results, which in the examples above, is when you call .ToList().
EF6 would only run the filter on the client if you called something like:
baza.CJE_DOC.ToList().Where(x => x.Field == value)
In this instance, it would retrieve the entire table when you called ToList(), and then use a client-side Linq query to filter the results in the where clause.

Answer 3

Any of the 3 will run the query on the SQL Server.
EF relies on LINQ's deferred execution model to build up an expression tree. Once you take an action that causes the expression to be enumerated (e.g. calling ToList(), ToArray(), or any of the other To*() methods), it will convert the expression tree to SQL, send the query to the server, and then start returning the results.
One of the side effects of this is that when using the query or lambda syntax, expressions that EF does not understand how to convert to SQL will cause an exception.
If you absolutely need to use some code that EF can't handle, you can break your code into multiple segments -- filtering things down as far as possible via code that can be converted to SQL, using the AsEnumerable() method to "close off" the EF expression, and doing your remaining filtering or transformations using Linq to Objects.