select sysdate,sysdate - interval ’7’ MINUTE from dual

select sysdate - interval ’7’ hour from dual

 select sysdate - interval ’7’ day from dual

select sysdate,sysdate - interval ’7’ month from dual

select sysdate,sysdate - interval ’7’ year from dual

select sysdate,sysdate - 8 *interval ’2’ hour from dual

select sysdate,to_char(sysdate,’yyyy-mm-dd hh24:mi:ss’) from dual

select sysdate,to_char(sysdate,’yyyy-mm-dd hh:mi:ss’) from dual

select sysdate,to_char(sysdate,’yyyy-ddd hh:mi:ss’) from dual

select sysdate,to_char(sysdate,’yyyy-mm iw-d hh:mi:ss’) from dual

select to_date(’2003-10-17 21:15:37’,’yyyy-mm-dd hh24:mi:ss’) from dual

select trunc(sysdate ,’YEAR’) from dual

select trunc(sysdate ) from dual

select to_char(trunc(sysdate ,’YYYY’),’YYYY’) from dual

--返回当前时间 年月日小时分秒毫秒

select to_char(current_timestamp(5),’DD-MON-YYYY HH24:MI:SSxFF’) from dual;

--返回当前 时间的秒毫秒，可以指定秒后面的精度(最大=9)

select to_char(current_timestamp(9),’MI:SSxFF’) from dual;

declare

type rc is ref cursor;

l_rc rc;

l_dummy all_objects.object_name%type;

l_start number default dbms_utility.get_time;

begin

for I in 1 .. 1000

loop

open l_rc for

’select object_name from all_objects ’||

’where object_id = ’ || i;

fetch l_rc into l_dummy;

close l_rc;

end loop;

dbms_output.put_line

( round( (dbms_utility.get_time-l_start)/100, 2 ) ||

’ seconds...’ );

end;