Except and insert problem entity?

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C#

entity-framework

Database name: S

Table: **STUDENT**

    ID   NAME   COUNTRYNO   AGE   BRANCHCODE
    ----------------------------------------
    1    Alex    001        25       05
    2    Mary    002        26       09

Database name: P

Table **PERSON**:

     NAME   COUNTRYNO   AGE   BRANCHCODE  
    ------------------------------------------
     John     127        45      04
     Elize    125        54      06


I want to new table:

Database name: S

Table **NEWPERSON**

     NAME   COUNTRYNO   AGE   BRANCHCODE  SITUATION
    ----------------------------------------------------
     John     127        45      04          0
     Elize    125        54      06          0

I want to compare the two tables (`countryno` and `branchcode`), and if I don't have the second table values, add them to the new table and situation get it 0.

But this code doesn't run. How to solve in Entity Framework?

What I have tried:

var student=DbContext.Entities.Student.Select(a=> new { CountryNo =a.CountryNo, BranchCode=a.BranchCode
    });     ------>  //studentcount:0
    
    var person=DbContext.Entities.Student.Select(a=> new { CountryNo =a.CountryNo, BranchCode=a.BranchCode
    });     ----> //personcount:0
    
    var common=person.Except(student);   -----> //common:0
    
    List<NEWPERSON> np= new List<NEWPERSON>();   ---> np:0
    foreach(var item in common)   //it doesnt enter loop
    {
        var ıtem=person.Single(persons=>persons.PERSON==item.PERSON && persons.CountryNo==item.CountryNo);
    if(tempItem !=null)
    {
        NEWPERSON newperson=new NEWPERSON
    {  
         CountryNo=item.CountryNo,
         BranchCode=item.BranchCode,
         Age=item.Age,
         Name=item.Name,
         Situation=0
    }
    np.Add(newperson);
    }
    
    }