Linq unable to hydrate an IEnumerable in a left outer join group by query -

i have left outer join group linq query:

var query = idef in taskdb.taskdefinitions  join iparam in taskdb.taskparameters     on idef.id equals iparam.taskid nullableparameters iparam in nullableparameters.defaultifempty()  join iexecution in executions     on idef.id equals iexecution.taskid nullableexecutions iexecution in nullableexecutions.defaultifempty()  group iparam new { definition = idef, execution = iexecution } g  select new querydomain {     definition = g.key.definition,     parameters = g,      execution = g.key.execution, };       public class querydomain     {         public taskdefinition definition { get; set; }         public ienumerable<taskparameter> parameters { get; set; }         public taskexecution execution { get; set; }     } 

the query keeps throwing

system.data.sqlclient.sqlexception (0x80131904): invalid object name   'dbo.taskparameter'. 

i stopped right before execution examine underlying sql statement, reason, doesn't seem select fields table taskparameter

select [t4].* (     select [t0].*, [t3].* [dbo].[taskdefinition] [t0] left outer join [dbo].[taskparameter] [t1] on [t0].[id] = [t1].[taskid] left outer join (     select 1 [test], [t2].* [dbo].[taskexecution] [t2]     ) [t3] on ([t0].[id] = [t3].[taskid]) , ([t3].[asof] = @p0) group [t0].*, [t3].* ) [t4] [t4].[cstype] = @p1 

i simplified query make easier read.

the sql works, didn't select values taskparameter.

anybody has idea happened?

at end, have 3 tables. taskdefinition main table. taskexecution may contain 0 or 1 entries indexing (fk) taskdefinition. taskparameter may contain number (>=0) of entries indexing (fk) taskdefinition. querydomain reflects desired structure of result of query. thanks.