select sysdate from dual;
select systimestamp from dual;select localtimestamp from dual;select current_timestamp from dual;select dbtimezone from dual;select sessiontimezone from dual;select to_timestamp('2015-11-06 10:35:00','yyyy.mm.dd hh24:mi:ss') from dual;
select to_char(sysdate,'yyyy.mm.dd hh24:mi:ss') from dual;systimestamp 数据库服务器当前的时间以及时区;
localtimestamp 客户端当前时间,不包含时区;
current_timestamp 客户端当前时区,包含客户端的时区。