SELECT      t.date_,
            t.id,
            t.cnt,
            o.count AS without_activities
FROM        table t
OUTER APPLY
            (
                   SELECT COUNT(*) AS count
                   FROM   table tt
                   WHERE  tt.date_ < t.date_
                   AND    tt.cnt = 0
                   AND    COALESCE(tt.date_ >
                          (
                                 SELECT MAX(ttt.date_)
                                 FROM   table ttt
                                 WHERE  ttt.date_<t.date_
                                 AND    ttt.cnt !=0), TRUE) ) o;