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04/02/2012

UNICODE (Transact-SQL)

依照 Unicode 標準所定義，傳回輸入運算式第一個字元的整數值。

語法

UNICODE ( 'ncharacter_expression' )

引數

'ncharacter_expression'
這是一個 nchar 或 nvarchar 運算式。

傳回類型

int

範例

A. 使用 UNICODE 和 NCHAR 函數

下列範例會利用 UNICODE 和 NCHAR 函數來列印 Åkergatan 24 個字元字串中第一個字元的 UNICODE 值，以及列印實際的第一個字元 Å。

DECLARE @nstring nchar(12)
SET @nstring = N'Åkergatan 24'
SELECT UNICODE(@nstring), NCHAR(UNICODE(@nstring))

以下為結果集：

----------- - 
197         Å

B. 使用 SUBSTRING、UNICODE 和 CONVERT

下列範例會利用 SUBSTRING、UNICODE 和 CONVERT 函數來列印 Åkergatan 24 字串中的字元數目、Unicode 字元，以及每個字元的 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(12)
-- 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, which 
-- indicates that the data following the N is Unicode data.
SET @nstring = N'Åkergatan 24'
-- 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)
-- While these are still characters in the character string,
   BEGIN
   SELECT @position, 
      CONVERT(char(17), SUBSTRING(@nstring, @position, 1)),
      UNICODE(SUBSTRING(@nstring, @position, 1))
   SELECT @position = @position + 1
   END

以下為結果集：

Character # Unicode Character UNICODE Value
                                          
----------- ----------------- ----------- 
1           Å                 197         
                                          
----------- ----------------- ----------- 
2           k                 107         
                                          
----------- ----------------- ----------- 
3           e                 101         
                                          
----------- ----------------- ----------- 
4           r                 114         
                                          
----------- ----------------- ----------- 
5           g                 103         
                                          
----------- ----------------- ----------- 
6           a                 97          
                                          
----------- ----------------- ----------- 
7           t                 116         
                                          
----------- ----------------- ----------- 
8           a                 97          
                                          
----------- ----------------- ----------- 
9           n                 110         
                                          
----------- ----------------- ----------- 
10                            32          
                                          
----------- ----------------- ----------- 
11          2                 50          
                                          
----------- ----------------- ----------- 
12          4                 52