CHR returns the character having the binary equivalent to
n as a
VARCHAR2 value in either the database character set or, if you specify
NCHAR_CS, the national character set.
For single-byte character sets, if
n > 256, then Oracle Database returns the binary equivalent of
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.
Use of the
CHR function (either with or without the optional
NCHAR_CS clause) results in code that is not portable between ASCII- and EBCDIC-based machine architectures.
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
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
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