Oracle Date Conversion __oracle

Oracle Date Conversion
Conversion functions
The biggest relationship with date operations is two conversion functions: To_date (), To_char ()
The to_date () action converts a character type to a date type in a certain format:
Specific usage: to_date (' 2004-11-27 ', ' yyyy-mm-dd '), the former is a string, the latter is the conversion date format, note that the two should be a corresponding.
such as; To_date (' 2004-11-27 13:34:43 ', ' yyyy-mm-dd hh24:mi:ss ') will be given a specific time of multiple date formats:
YYYY: four-bit year
Yyy,yy,y: Last three-bit, two-bit, or one-digit of year, defaults to current century
Month Number of mm:01~12
MONTH: Month of nine characters, padding on right with space
MON: Month abbreviation for three-bit characters
WW: Week of the Year
D: Day of the week
DD: Day of the month
DDD: The first day of the year
Day: The full name of the days of nine characters, padded with spaces on the right
Hh,hh12: The first few hours of the day, the 12 notation
HH24: The first few hours of the day, with a value of 00~23
MI: minutes in one hour
SS: seconds in one minute
SSSS: The number of seconds since midnight
To_char (): Convert date to character type in a certain format
Sql> Select To_char (sysdate, ' yyyy-mm-dd hh24:mi:ss ') time from dual;