The following table describes the functions that convert strings to specific data types and vice versa. Those functions are used when the required input/output format of a specific DATE/TIMESTAMP is different from the default DATE/TIMESTAMP formats. The default DATE format is: YYYY-MM-DD The default TIMESTAMP format is: YYYY-MM-DD HH24:MI:SS.MS In all the functions below, the first argument is the value to be converted and the second argument is a template that defines the output or input format. The input string is of one of the Character types.
FunctionDescription and CommentsExample
TO_DATE(STRING, format)Converts string to DATE according to the given format
Returns DATE		to_date('21 Jun 2023', 'dd mon YYYY')
=> 2023-06-21
TO_TIMESTAMP(STRING, format)Converts string to TIMESTAMP according to the given format
Returns TIMESTAMP		TO_TIMESTAMP('_2023-12-13_ 04:05:06.789', 'yyyy-dd-mm hh24:mi:ss.ms')
=> 2023-12-13 04:05:06.789
TO_CHAR(DATE, format)
TO_CHAR(TIMESTAMP, format)		Converts a DATE or TIMESTAMP data type to a string in the given format
Returns VARCHAR
See notes		TO_CHAR(date '2022-12-12', 'yy-mm-dd')
=> 22-12-12

TO_CHAR(TIMESTAMP '2022-12-24 16:27:30', 'dd-mm-yyyy HH12:MI:SS am')
=> 24-12-2022 04:27:30 pm
Template Patterns for Date/Time Formatting:
PatternDescription and Comments
HHhour of day (01-12)
HH12hour of day (01-12)
HH24hour of day (00-23)
MIminute (00-59)
SSsecond (00-59)
MSmillisecond (000-999)
USmicrosecond (000000-999999)
YYYYyear (4 digits)
YYlast 2 digits of year
MMmonth number (01-12)
MonFirst three letters of the month (‘Jan’, ‘Feb’, and so on)
DDday of month (01-31)
AM, am, PM, pmmeridiem indicator

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Examples

Convert the input format to a DATE/TIMESTAMP that can identified as such: 
SELECT TO_DATE('2012-JAN-12','YYYY-MON-DD');
SELECT TO_DATE('20/12/12','YY/MM/DD');
SELECT TO_DATE('2012.07.23', 'YYYY.MM.DD');
SELECT TO_DATE('20200526','YYYYMMDD');
SELECT TO_TIMESTAMP('20/12/12 17:12:12.45','YY/MM/DD HH24:MI:SS.MS');
SELECT TO_TIMESTAMP('2010-Aug-09 12:00:01 PM' , 'yyyy-Mon-dd HH:MI:SS PM');
Convert the DATE/TIMESTAMP to the desired output format: 
SELECT TO_CHAR(TIMESTAMP '2022-12-12 16:27:30.41', 'dd-mm-yyyy HH12:MI:SS
am');
SELECT TO_CHAR(date_column, 'YY-MM-DD HH:MI:SS.MS AM') FROM my_table;