The TO_TIME function interprets a character string based on the time format given as an argument, converts it to a TIME type value, and returns it. For the format, see TO_CHAR Function (date_time). If a format is not specified, the "HH:MI:SS" format is applied by default.
TO_TIME(string_argument[,format_argument [,date_lang_string_literal]]):
string_argument :
• character strings
• NULL
format_argument :
• character strings (see Date/Time Format 1)
• NULL
date_lang_string_literal : (see date_lang_string_literal)
• 'en_US'
• 'ko_KR'
--selecting a time type value casted from a string in the specified format
SELECT TO_TIME ('13:10:30');
to_time('13:10:30')=============================================
01:10:30 PM
SELECT TO_TIME('HOUR: 13 MINUTE: 10 SECOND: 30', '"HOUR:" HH24 "MINUTE:" MI "SECOND:" SS');
to_time('HOUR: 13 MINUTE: 10 SECOND: 30', '"HOUR:" HH24 "MINUTE:" MI "SECOND:" SS', 'en_US')=============================================
01:10:30 PM
SELECT TO_TIME ('13:10:30', 'HH24:MI:SS');
to_time('13:10:30', 'HH24:MI:SS', 'en_US')
=============================================
01:10:30 PM
SELECT TO_TIME ('13:10:30', 'HH12:MI:SS');
ERROR: Conversion error in date format.