select 
 j.patient,
 TO_CHAR(j.REGISTER_DATE, 'HH24.MI.SS') as " Время регистрации",
 j.REGISTER_DATE,
 patient_surname as "Поступил",
 TO_CHAR(h.date_in, 'HH24.MI.SS') as " Время поступления ",
 h.date_in
 from D_V_HPK_PLAN_JOURNALS j
 join D_V_REP_HOSPHISTORY_HEAD h on h.hosp_history_id = j.id
 
 where id = (select max(id) from D_V_HPK_PLAN_JOURNALS );

select 
        TO_TIMESTAMP('11:00:00',' HH24:MI:SS' ) -
        TO_TIMESTAMP(' 12:30:00',' HH24:MI:SS' ) as datedif
         
          from dual;

[SRC oracle]

 select 
          sysdate,
          sysdate - interval '02:01:00' HOUR TO SECOND
          from dual;

select
TO_CHAR(j.REGISTER_DATE, 'HH24.MI.SS') as " Время регистрации",
 
TO_CHAR(h.date_in, 'HH24.MI.SS') as " Время поступления "

from D_V_HPK_PLAN_JOURNALS j
join D_V_REP_HOSPHISTORY_HEAD h on h.hosp_history_id = j.id