In Oracle Database, the NLS_CHARSET_NAME() function returns the character set name of a given character set, based on its ID. You pass the character set ID as an argument, and the function returns its name.

Syntax

The syntax goes like this:

NLS_CHARSET_NAME(number)

Where number is the character set ID for which you want to return the name.

Example

Here’s a basic example:

SELECT NLS_CHARSET_NAME(1)
FROM DUAL;

Result:

US7ASCII

Here it is with a different character set ID:

SELECT NLS_CHARSET_NAME(871)
FROM DUAL;

Result:

UTF8

Null Argument

If the argument is null, the result is null:

SET NULL 'null';
SELECT NLS_CHARSET_NAME(null)
FROM DUAL;

Result:

null

By default, SQLcl and SQL*Plus return a blank space whenever null occurs as a result of a SQL SELECT statement.

However, you can use SET NULL to specify a different string to be returned. Here I specified that the string null should be returned.

Invalid Character Set ID

Passing an invalid character set ID results in null:

SET NULL 'null';
SELECT NLS_CHARSET_NAME(19999)
FROM DUAL;

Result:

null

However, passing the wrong data type returns an error:

SELECT NLS_CHARSET_NAME('oops')
FROM DUAL;

Result:

Error starting at line : 1 in command -
SELECT NLS_CHARSET_NAME('oops')
FROM DUAL
Error report -
ORA-01722: invalid number

Incorrect Argument Count

Calling the function without passing any arguments results in an error:

SELECT NLS_CHARSET_NAME()
FROM DUAL;

Result:

Error starting at line : 1 in command -
SELECT NLS_CHARSET_NAME()
FROM DUAL
Error at Command Line : 1 Column : 8
Error report -
SQL Error: ORA-00938: not enough arguments for function
00938. 00000 -  "not enough arguments for function"
*Cause:    
*Action:

But passing multiple character set IDs results in the name of the first one being returned:

SELECT NLS_CHARSET_NAME(871, 1)
FROM DUAL;

Result:

UTF8