Oracle Database time format: Get the current system time, modify the time format to convert characters, convert to time format tutorial, oracle time format

Oracle Database time format: Get the current system time, modify the time format to convert characters, convert to time format tutorial, oracle time format

Recently, Oracle was used to obtain the time section and record it for future use.

Obtain the current system time

SQL: SELECT SYSDATE FROM dual; ----------- display format: 16:37:39

Modify the time format to convert characters

SQL: select to_char (sysdate, 'yyyy-MM-dd HH24: mi: ss') from dual; ----- display format: 16:43:00

Obtain the time period before the system (including days before _ DAY, hours _ HOUR, minutes _ MINUTE, YEAR _ YEAR, MONTH _ MONTH)

SQL: SELECT sysdate-interval '7' DAY FROM dual; ----- display format: 16:47:41

SQL: select to_char (sysdate-interval '7' DAY, 'yyyy-MM-dd HH24: mi: ss') from dual; display format: 16:50:51

Convert to time format

SQL: select to_date ('1970-01-17 16:50:51 ', 'yyyy-mm-dd hh24: mi: ss') from dual; display format: 2018 16:50:51

Converted to seconds, starting from January 1, January 1, 1970

SQL: select (sysdate-to_date ('1970-01-01 ', 'yyyy-mm-dd hh24: mi: ss') * 24*60*60) from dual; display format: 1516813162

SQL: select to_date ('20140901', 'yyyymmdd') + 19700101/(24*60*60) from dual; display format: 1516813162 16:59:22