LINQ To Entities中的日期不同？

I have:

select distinct 
       to_date(to_char(i.fe_stax, 'DD/MM/YYYY'), 'DD/MM/YYYY') FechaProg,
       a.id_ciud, t.no_ciud 
from itinerario i
where to_date(to_char(i.fe_stax, 'DD/MM/YYYY'), 'DD/MM/YYYY') is not null 
select distinct 
       to_date(to_ch