Actual time processing steps in Oracle Database

The following articles mainly describe the actual operation steps of time processing in the Oracle database. We will describe the instance in the form of 4824 hours, and we will use HH24 to display it, the following is an analysis of the specific content of the article. I hope you will gain some benefits.

 
 

  
  
select to_char(sysdate,'yyyy-MM-dd HH24:mi:ss') from dual;  
  
  
select to_date('2005-01-01 13:14:20','yyyy-MM-dd HH24:mi:ss') from dual;  
  
  
to_date() function  
 
 

1. Description of date format parameters

D. day of the week

The name of DAY, which is filled with spaces to 9 characters.

Day of DD month

The day of the year in DDD

Short Name of DY day

Week of the Year of the iw iso Standard

Four-digit year of the iyyy iso Standard

YYYY four-digit year

Last three digits of YYY, YY, and Y years, two digits, one digit

HH hours, at 12 hours

HH24 hours, in 24 hours

MI score

SS seconds

MM Month

Abbreviated month of Mon

Full name of Month

W the week of the month

The day of the week in WW 1. Date interval operation

Current Time minus 7 minutes

 
 

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

Current Time minus 7 hours

 
 

  
  
select sysdate - interval '7' hour from dual 
 
 

Current Time minus 7 days

 
 

  
  
select sysdate - interval '7' day from dual 
 
 

Current Time minus July

 
 

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

Current Time minus 7 years

 
 

  
  
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 operations

 
 

  
  
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 Oracle database documentation (ORACLE901DOC/SERVER.901/A90125/SQL _ELEMENTS4.HTM #48515)

3. Character-to-date operations

 
 

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

The usage is similar to that of to_char.