Linq Group by / Distinct with Join table -

i plan join 2 table, , distinct value of language column. how should achieve in linq? try add 'group' no luck. besides, want select s value r distinct language value.

my code:

 public actionresult questionlink(int survey_id)         {             var query = r in db.surv_question_ext_model                         join s in db.surv_question_model                         on r.qext_question_id equals s.question_id                         s.question_survey_id == survey_id                         group r.language << not work **                         select r;              return partialview(query.tolist());         }  

this in morelinq called distinctby. if method works on ienumerable, can't use in ef query. can use same approach:

var query = r in db.surv_question_ext_model             join s in db.surv_question_model on r.qext_question_id equals s.question_id             s.question_survey_id == survey_id             group new { r, s } r.language grp             select grp.firstordefault(); 

but wonder if want. result depends on ordering of languages database happens return. think should add predicate specific language , remove grouping:

var query = r in db.surv_question_ext_model             join s in db.surv_question_model             on r.qext_question_id equals s.question_id             s.question_survey_id == survey_id                && r.language == somevariable             select new { r, s };