The TIMESTAMP function returns a timestamp from a value or a pair
The rules for the arguments depend on whether the second argument
If only one argument is specified: It must be a timestamp, a valid string
representation of a timestamp, or a string of length 14 that is not a CLOB,
LONG VARCHAR, or XML value. A string of length 14 must be a string of digits
that represents a valid date and time in the form yyyyxxddhhmmss, where yyyy is
the year, xx is the month, dd is the day, hh is the hour, mm is
the minute, and ss is the seconds.
If both arguments are specified: The first argument must be a date or
a valid string representation of a date and the second argument must be a
time or a valid string representation of a time.
The other rules depend on whether the second argument is specified:
If both arguments are specified: The result is a timestamp with the date
specified by the first argument and the time specified by the second argument.
The microsecond part of the timestamp is zero.
If only one argument is specified and it is a timestamp: The result is
If only one argument is specified and it is a string: The result is the
timestamp represented by that string. If the argument is a string of length
14, the timestamp has a microsecond part of zero.
TIMESTAMP ( expression [, expression ] )
The second column in table records_table contains
dates (such as 1998-12-25) and the third column contains times of day (such
as 17:12:30). You can return the timestamp with this statement:
SELECT TIMESTAMP(col2, col3) FROM records_table
following clause returns the value 1998-12-25-17:12:30.0: