This function is used to convert a date into a string in a specified format.

to_char(string date, string format)

**Table 1** Parameters
Parameter	Mandatory	Type	Description
date	Yes	DATE or STRING	Date that needs to be processed The following formats are supported: yyyy-mm-dd yyyy-mm-dd hh:mi:ss yyyy-mm-dd hh:mi:ss.ff3
format	Yes	STRING	Format of the date to be converted Constant of the STRING type. Extended date formats are not supported. The value is a combination of the time unit (year, month, day, hour, minute, and second) and any character. YYYY or yyyy indicates the year. MM indicates the month. mm indicates the minute. dd indicates the day. HH indicates the 24-hour clock. hh indicates the 12-hour clock. mi indicates the minute. ss indicates the second. SSS indicates millisecond.

The return value is of the STRING type.

If the value of date is not of the DATE or STRING type, the error message "data type mismatch" is displayed.
If the value of date is of the DATE or STRING type but is not in one of the supported formats, NULL is returned.
If the value of format is NULL, NULL is returned.

The static data 2023-08*16 is returned.

select to_char('2023-08-16 10:54:36','Example static data yyyy-mm*dd');

The value 20230816 is returned.

select to_char('2023-08-16 10:54:36', 'yyyymmdd');

The value NULL is returned.

select to_char('Example static data 2023-08-16','Example static data yyyy-mm*dd');

The value NULL is returned.

select to_char('20230816', 'yyyy');

The value NULL is returned.

select to_char('2023-08-16 10:54:36', null);