c# - Get all users, only when they don't occur in another table -

i have 2 tables. 1 user table , 1 table in results placed of test.

when user takes test result , user_id placed in results table. when user never took test user_id won't in results table.

i need users not in results table. there way in 1 query? (entity framework)

getting users easy. need way link results table see of users want in result set.

(from u in entity.users [where not in results table..??] select u);  

fully working example, using mock objects:

using system; using system.collections.generic; using system.linq; using system.text;  namespace consoleapplication1 {     class program     {         static void main(string[] args)         {              var userstakentest = new list<string>() { "bob", "jim", "angel" };             var allusers = new list<string> { "bob", "jim", "angel", "mike", "jimbobhouse" };              var users = user in allusers                         join usertakentest in userstakentest on user equals usertakentest tempusers                         newusers in tempusers.defaultifempty()                         string.isnullorempty(newusers)                         select user;              foreach (var user in users)             {                 console.writeline("this user has not taken test: " + user);             }             console.readline();         }     } } 

.defaultifempty() after - if brings empty result have object in table not show in table b.