The CURRENT_TIMESTAMP, CURRENT_TIMESTAMP(), SYS_TIMESTAMP, SYSTIMESTAMP, LOCALTIME, LOCALTIME(), LOCALTIMESTAMP, and LOCALTIMESTAMP() are used interchangeably, and they return the current date and time as TIMESTAMP type. The unit is second.
If you define DEFAULT value for column initial value and specify the initial value to SYS_DATETIME, the default value is specified to the timestamp at the time of creating a table, not inserting a table. Note that the default value is not specified in case of INSERT. Therefore, you must specify SYS_DATETIME in the VALUES of INSERT statement upon inserting data.
CURRENT_TIMESTAMP
CURRENT_TIMESTAMP()
SYS_TIMESTAMP
SYSTIMESTAMP
LOCALTIME
LOCALTIME()
LOCALTIMESTAMP
LOCALTIMESTAMP()
--it returns the current date and time in TIMESTAMP type
SELECT LOCALTIME, SYS_TIMESTAMP;
SYS_TIMESTAMP SYS_TIMESTAMP
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07:00:48 PM 04/01/2010 07:00:48 PM 04/01/2010
--it returns the timestamp value 1 hour added to the current sys_timestamp value
SELECT CURRENT_TIMESTAMP()+3600;
SYS_TIMESTAMP +3600
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08:02:42 PM 04/01/2010