Oracle Time Operation __oracle

1. Date-time interval operation
Current time minus 7 minutes of time
Select Sysdate,sysdate-interval ' 7 ' MINUTE from dual
The current time minus 7 hours of time
Select Sysdate-interval ' 7 ' hour from dual
The current time minus 7 days
Select Sysdate-interval ' 7 ' from dual
Current time minus July time
Select Sysdate,sysdate-interval ' 7 ' month from dual
The current time minus 7 years time
Select Sysdate,sysdate-interval ' 7 ' from dual
Time interval multiplied by a number
Select Sysdate,sysdate-8 *interval ' 2 ' hour from dual
2. Date to character operation
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
Refer to Oracle's related documentation (ORACLE901DOC/SERVER.901/A90125/SQL_ELEMENTS4. htm#48515)
3. Character to date operation
Select To_date (' 2003-10-17 21:15:37 ', ' yyyy-mm-dd hh24:mi:ss ') from dual
The specific usage is similar to the to_char above.
4. Use of Trunk/round function
Select Trunc (Sysdate, ' year ') from dual
Select Trunc (sysdate) from dual
Select To_char (trunc (sysdate, ' YYYY '), ' YYYY ') from dual
5.oracle data type with millisecond level
--Returns the current time, day, hour, and millisecond.
Select To_char (Current_timestamp (5), ' dd-mon-yyyy HH24:MI:SSxFF ') from dual;
--Returns the second millisecond of the current time, specifying the precision after the second (Max =9)
Select To_char (Current_timestamp (9), ' Mi:ssxff ') from dual;
6. Calculation program Running time (MS)
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