Oracle Date function 2!

1. Date-time interval operation

Time minus 7 minutes for the current 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 ' Day from dual
Time minus July for current time
Select Sysdate,sysdate-interval ' 7 ' month from dual
Time minus 7 years in the current time
Select Sysdate,sysdate-interval ' 7 ' year from dual
Time interval multiplied by a number
Select Sysdate,sysdate-8 *interval ' 2 ' hour from dual

2. Date-to-character manipulation
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 the related documentation for Oracle (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 concrete usage is similar to the to_char above.

4. Use of the 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 types with millisecond levels
--Returns the current time, month, day, hour, minute, 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 seconds (Max =9)
Select To_char (Current_timestamp (9), ' Mi:ssxff ') from dual;

6. Calculate when the program is running (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

Http://www.cnblogs.com/fjfzhkb/archive/2007/10/26/938421.html

Oracle Date function 2!