c# - Linq, date comparison -

i need npgsql query convert linq query. npgsql looks like:

p.cmd = new npgsqlcommand("select distinct min(h_dt::date) w_h " +                                     "inner join on h_us_id = us_id " +                                     "where cat_id != '' , h_dt::date not in (select distinct period_date m_v " +                                     "where mv_id = 1)", conn); 

i try convert:

var q = (from t in context.w_h          join t1 in context.us          on t.h_us_id equals t1.us_id          t1.cat_id != ""          select t.h_dt)         .min(); 

i need in adding part of comparison:

and h_dt::date not in (select distinct period_date m_v)

h_dt::date - return date in format yyyy-mm-dd

have collection hold results:

// pseudocode ! write selection here: var v = select distinct period_date m_v 

and compare contains:

q.where(i=> ! v.contains(i) );