How is the to_char() function used in Oracle?

In Oracle database, the TO_CHAR() function is used to convert dates, numbers, or other data types into character format. Its basic syntax is as follows:

TO_CHAR(expression, format_mask)

expression is the data to be converted, and format_mask is the format to convert the data into.

For example, converting dates into a string of a specific format:

SELECT TO_CHAR(sysdate, 'YYYY-MM-DD HH24:MI:SS') FROM dual;

Convert numbers into a specific format of strings.

SELECT TO_CHAR(12345, '99999') FROM dual;

For more detailed formatting options, refer to the official Oracle documentation.