Sysdate is not updating to a column

Question

I have a query that update column to sysdate. The problem sometimes it updates but sometimes not.
Here is my sample query.
Update table1 set a= 'a', b='b', c=SYSDATE where table1.no = '1'
Is there any issue of a SYSDATE.
Thanks a lot!

Answer 1

... and this is what language?
SQL> drop table tst purge
  2  /
Table dropped.
SQL>
SQL> create table tst
  2  (a varchar2(1)
  3  ,b varchar2(1)
  4  ,c date
  5  );
Table created.
SQL>
SQL> insert into tst values ('A', 'B', sysdate);
1 row created.
SQL> select a
  2       , b
  3       , to_char (c, 'hh24:mi:ss')
  4    from tst
  5  ;
A B TO_CHAR(
A B 10:30:33
SQL> begin
  2     dbms_lock.sleep (1);
  3  end;
  4  /
PL/SQL procedure successfully completed.
SQL>
SQL> update tst
  2     set a = 'a'
  3       , b = 'b'
  4       , c = sysdate
  5  ;
1 row updated.
SQL> select a
  2       , b
  3       , to_char (c, 'hh24:mi:ss')
  4    from tst
  5  ;
A B TO_CHAR(
a b 10:30:34
SQL> Are you executing the same statement within the same second (granularity of DATE) multiple times?