Oracle® Database SQL Reference 10g Release 2 (10.2) Part Number B14200-01 |
|
|
View PDF |
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 theCHR 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 2-10, "Implicit Type Conversion Matrix" for more information on implicit conversion |
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. That is, you must specify:
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 uses the UTF8 character set:
SELECT CHR (50052 USING NCHAR_CS) FROM DUAL; CH -- Ä