The TIME function extracts the time part from specified argument and returns it in the 'HH:MM:SS' format. You can specify the TIME, TIMESTAMP, or DATETIME type; the value is returned in VARCHAR type.
TIME(time)
SELECT TIME('12:34:56');
time('12:34:56')
======================
'12:34:56.000'
SELECT TIME('2010-01-01 12:34:56');
time('2010-01-01 12:34:56')
======================
'12:34:56.000'
SELECT TIME(datetime'2010-01-01 12:34:56');
time(datetime '2010-01-01 12:34:56')
======================
'12:34:56.000'
SELECT TIME('invalid_string');
ERROR: ERROR: Conversion error in time format.