NCHAR (Transact-SQL)
根据 Unicode 标准的定义,返回具有指定的整数代码的 Unicode 字符。
语法
NCHAR ( integer_expression )
参数
integer_expression
介于 0 与 65535 之间的正整数。如果指定了超出此范围的值,将返回 NULL。
返回类型
nchar(1)
示例
A. 使用 NCHAR 和 UNICODE
以下示例使用 UNICODE
和 NCHAR
函数打印 København
字符串中第二个字符的 UNICODE
值和 NCHAR
(Unicode 字符),并打印实际的第二个字符
。
DECLARE @nstring nchar(8)
SET @nstring = N'København'
SELECT UNICODE(SUBSTRING(@nstring, 2, 1)),
NCHAR(UNICODE(SUBSTRING(@nstring, 2, 1)))
GO
下面是结果集:
----------- -
248 ?1 row(s) affected)
B. 使用 SUBSTRING、UNICODE、CONVERT 和 NCHAR
以下示例使用 SUBSTRING
、UNICODE
、CONVERT
和 NCHAR
函数打印字符串 København
中的字符数、Unicode 字符和每个字符的 UNICODE 值。
-- The @position variable holds the position of the character currently
-- being processed. The @nstring variable is the Unicode character
-- string to process.
DECLARE @position int, @nstring nchar(9)
-- Initialize the current position variable to the first character in
-- the string.
SET @position = 1
-- Initialize the character string variable to the string to process.
-- Notice that there is an N before the start of the string. This
-- indicates that the data following the N is Unicode data.
SET @nstring = N'København'
-- Print the character number of the position of the string you are at,
-- the actual Unicode character you are processing, and the UNICODE
-- value for this particular character.
PRINT 'Character #' + ' ' + 'Unicode Character' + ' ' + 'UNICODE Value'
WHILE @position <= DATALENGTH(@nstring)
BEGIN
SELECT @position,
NCHAR(UNICODE(SUBSTRING(@nstring, @position, 1))),
CONVERT(NCHAR(17), SUBSTRING(@nstring, @position, 1)),
UNICODE(SUBSTRING(@nstring, @position, 1))
SELECT @position = @position + 1
END
GO
下面是结果集:
Character # Unicode Character UNICODE Value
----------- ---- ----------------- -----------
1 K K 75
(1 row(s) affected)
----------- ---- ----------------- -----------
2 ? ? 248
(1 row(s) affected)
----------- ---- ----------------- -----------
3 b b 98
(1 row(s) affected)
----------- ---- ----------------- -----------
4 e e 101
(1 row(s) affected)
----------- ---- ----------------- -----------
5 n n 110
(1 row(s) affected)
----------- ---- ----------------- -----------
6 h h 104
(1 row(s) affected)
----------- ---- ----------------- -----------
7 a a 97
(1 row(s) affected)
----------- ---- ----------------- -----------
8 v v 118
(1 row(s) affected)
----------- ---- ----------------- -----------
9 n n 110
(1 row(s) affected)
----------- ---- ----------------- -----------
10 NULL NULL
(1 row(s) affected)
----------- ---- ----------------- -----------
11 NULL NULL
(1 row(s) affected)
----------- ---- ----------------- -----------
12 NULL NULL
(1 row(s) affected)
----------- ---- ----------------- -----------
13 NULL NULL
(1 row(s) affected)
----------- ---- ----------------- -----------
14 NULL NULL
(1 row(s) affected)
----------- ---- ----------------- -----------
15 NULL NULL
(1 row(s) affected)
----------- ---- ----------------- -----------
16 NULL NULL
(1 row(s) affected)
----------- ---- ----------------- -----------
17 NULL NULL
(1 row(s) affected)
----------- ---- ----------------- -----------
18 NULL NULL
(1 row(s) affected)
请参阅
参考
数据类型 (Transact-SQL)
字符串函数 (Transact-SQL)
UNICODE (Transact-SQL)