CURRENT_DATETIME, CURRENT_DATETIME(), NOW() SYS_DATETIME, and SYSDATETIME are used interchangeably, and they return the current date and time in DATETIME type. The unit is millisecond.
CURRENT_DATETIME
CURRENT_DATETIME()
NOW()
SYS_DATETIME
SYSDATETIME
--it returns the current date and time in DATETIME type
SELECT NOW(), SYS_DATETIME;
SYS_DATETIME SYS_DATETIME
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04:08:09.829 PM 02/04/2010 04:08:09.829 PM 02/04/2010
--it returns the timestamp value 1 hour added to the current sys_datetime value
SELECT TO_CHAR(SYSDATETIME+3600*1000, 'YYYY-MM-DD HH:MI');
to_char( SYS_DATETIME +3600*1000, 'YYYY-MM-DD HH:MI', 'en_US')
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'2010-02-04 04:08'