CHR

Syntax

Purpose

CHR returns the character having the binary equivalent to n as a VARCHAR2 value in either the database character set or, if you specify USING NCHAR_CS, the national character set.

For single-byte character sets, if n > 256, then Oracle Database returns the binary equivalent of n mod 256. For multibyte character sets, n must resolve to one entire code point. Invalid code points are not validated, and the result of specifying invalid code points is indeterminate.

This function takes as an argument a NUMBER value, or any value that can be implicitly converted to NUMBER, and returns a character.

Note:

Use of the CHR function (either with or without the optional USING NCHAR_CS clause) results in code that is not portable between ASCII- and EBCDIC-based machine architectures.

See Also:

NCHR and Table 2-8 for more information on implicit conversion
Appendix C in Oracle Database Globalization Support Guide for the collation derivation rules, which define the collation assigned to the character return value of CHR

Examples

The following example is run on an ASCII-based machine with the database character set defined as WE8ISO8859P1:

SELECT CHR(67)||CHR(65)||CHR(84) "Dog"
  FROM DUAL;

Dog
---
CAT

To produce the same results on an EBCDIC-based machine with the WE8EBCDIC1047 character set, the preceding example would have to be modified as follows:

SELECT CHR(195)||CHR(193)||CHR(227) "Dog"
  FROM DUAL; 

Dog 
--- 
CAT

For multibyte character sets, this sort of concatenation gives different results. For example, given a multibyte character whose hexadecimal value is a1a2 (a1 representing the first byte and a2 the second byte), you must specify for n the decimal equivalent of 'a1a2', or 41378:

SELECT CHR(41378)
  FROM DUAL;

You cannot specify the decimal equivalent of a1 concatenated with the decimal equivalent of a2, as in the following example:

SELECT CHR(161)||CHR(162)
  FROM DUAL;

However, you can concatenate whole multibyte code points, as in the following example, which concatenates the multibyte characters whose hexadecimal values are a1a2 and a1a3:

SELECT CHR(41378)||CHR(41379)
  FROM DUAL;

The following example assumes that the national character set is UTF16:

SELECT CHR (196 USING NCHAR_CS)
  FROM DUAL; 

CH 
-- 
Ä