将 SQL Server 中的文本值从 UTF8 转换为 ISO 8859-1答案

【问题标题】：Convert text value in SQL Server from UTF8 to ISO 8859-1将 SQL Server 中的文本值从 UTF8 转换为 ISO 8859-1
【发布时间】：2015-03-25 22:11:28
【问题描述】：

我在 SQL Server 中有一个使用 ~~utf8~~ SQL_Latin1_General_CP1_CI_AS 编码的列。如何以 ISO 8859-1 编码转换和保存文本？我想在 SQL Server 上进行查询。有什么建议吗？

奥莱。 Gostei do jogo。 Quando “baixei” até achei que não iria curtir muito

【问题讨论】：

由于 SQL Server 确实不支持 UTF-8 - 这将是一个挑战！
列的数据类型是什么：nvarchar、varchar 或 varbinary？它是存储为纯文本还是百分比编码？
以纯文本形式存储，属于文本类型。我在问题中添加了一个 sn-p

标签： sql sql-server encoding utf-8 iso-8859-1

【解决方案1】：

我编写了一个函数来修复存储在 varchar 字段中的 UTF-8 文本。

要检查固定值，您可以像这样使用它：

CREATE TABLE #Table1 (Column1 varchar(max))

INSERT #Table1
VALUES ('OlÃ¡. Gostei do jogo. Quando "baixei" atÃ© achei que nÃ£o iria curtir muito')

SELECT *, NewColumn1 = dbo.DecodeUTF8String(Column1)
FROM Table1
WHERE Column1 <> dbo.DecodeUTF8String(Column1)

输出：

Column1
-------------------------------
OlÃ¡. Gostei do jogo. Quando "baixei" atÃ© achei que nÃ£o iria curtir muito

NewColumn1
-------------------------------
Olá. Gostei do jogo. Quando "baixei" até achei que não iria curtir muito

代码：

CREATE FUNCTION dbo.DecodeUTF8String (@value varchar(max))
RETURNS nvarchar(max)
AS
BEGIN
    -- Transforms a UTF-8 encoded varchar string into Unicode
    -- By Anthony Faull 2014-07-31
    DECLARE @result nvarchar(max);

    -- If ASCII or null there's no work to do
    IF (@value IS NULL
        OR @value NOT LIKE '%[^ -~]%' COLLATE Latin1_General_BIN
    )
        RETURN @value;

    -- Generate all integers from 1 to the length of string
    WITH e0(n) AS (SELECT TOP(POWER(2,POWER(2,0))) NULL FROM (VALUES (NULL),(NULL)) e(n))
        , e1(n) AS (SELECT TOP(POWER(2,POWER(2,1))) NULL FROM e0 CROSS JOIN e0 e)
        , e2(n) AS (SELECT TOP(POWER(2,POWER(2,2))) NULL FROM e1 CROSS JOIN e1 e)
        , e3(n) AS (SELECT TOP(POWER(2,POWER(2,3))) NULL FROM e2 CROSS JOIN e2 e)
        , e4(n) AS (SELECT TOP(POWER(2,POWER(2,4))) NULL FROM e3 CROSS JOIN e3 e)
        , e5(n) AS (SELECT TOP(POWER(2.,POWER(2,5)-1)-1) NULL FROM e4 CROSS JOIN e4 e)
    , numbers(position) AS
    (
        SELECT TOP(DATALENGTH(@value)) ROW_NUMBER() OVER (ORDER BY (SELECT NULL))
        FROM e5
    )
    -- UTF-8 Algorithm (http://en.wikipedia.org/wiki/UTF-8)
    -- For each octet, count the high-order one bits, and extract the data bits.
    , octets AS
    (
        SELECT position, highorderones, partialcodepoint
        FROM numbers a
        -- Split UTF8 string into rows of one octet each.
        CROSS APPLY (SELECT octet = ASCII(SUBSTRING(@value, position, 1))) b
        -- Count the number of leading one bits
        CROSS APPLY (SELECT highorderones = 8 - FLOOR(LOG( ~CONVERT(tinyint, octet) * 2 + 1)/LOG(2))) c
        CROSS APPLY (SELECT databits = 7 - highorderones) d
        CROSS APPLY (SELECT partialcodepoint = octet % POWER(2, databits)) e
    )
    -- Compute the Unicode codepoint for each sequence of 1 to 4 bytes
    , codepoints AS
    (
        SELECT position, codepoint
        FROM
        (
            -- Get the starting octect for each sequence (i.e. exclude the continuation bytes)
            SELECT position, highorderones, partialcodepoint
            FROM octets
            WHERE highorderones <> 1
        ) lead
        CROSS APPLY (SELECT sequencelength = CASE WHEN highorderones in (1,2,3,4) THEN highorderones ELSE 1 END) b
        CROSS APPLY (SELECT endposition = position + sequencelength - 1) c
        CROSS APPLY
        (
            -- Compute the codepoint of a single UTF-8 sequence
            SELECT codepoint = SUM(POWER(2, shiftleft) * partialcodepoint)
            FROM octets
            CROSS APPLY (SELECT shiftleft = 6 * (endposition - position)) b
            WHERE position BETWEEN lead.position AND endposition
        ) d
    )
    -- Concatenate the codepoints into a Unicode string
    SELECT @result = CONVERT(xml,
        (
            SELECT NCHAR(codepoint)
            FROM codepoints
            ORDER BY position
            FOR XML PATH('')
        )).value('.', 'nvarchar(max)');

    RETURN @result;
END
GO

【讨论】：

你能解释一下吗？我将如何使用它来转换我的列值？
我在存储过程中添加了一些代码cmets。我还修复了 SQL Server 2012 之前版本中的 LOG 错误。
这个函数会在破坏 xml 编码的字符上失败，我不得不参考这篇文章来防止 xml 解析错误：stackoverflow.com/a/38117491/2578505
这个函数似乎不处理代理字符（基本多语言平面之外的 Unicode 字符）。例如，尝试SELECT dbo.DecodeUTF8String(N'abcÄƒÃ¢Ã®È™È›ðŸ˜€âœ”?')，它应该产生abcăâîșț?✔?，但它只输出abcăâîșț✔?。
是否有等效的编码？我似乎找不到正确编码值的解决方案，例如“سلام جیران”、“В России Base64 кодирует вас”、“❤️????⛄??????”，我尝试过的每种编码方法都是垃圾。 ..也许这需要成为一个问题。我可以用 .NET、C++ 等对它们进行编码，我得到一个可以解码的字符串。 "2LPZhNin2YUg2KzbjNix2KfZhg==", "0JIg0KDQvtGB0YHQuNC4IEJhc2U2NCDQutC+0LTQuNGA0YPQtdGCINCy0LDRgQ=="和"4p2k77iP8J+SpfCfpKrwn6aM8J+OheKbhPCfjoTwn6SQ8J+ZiSPCQf=n=n。

【解决方案2】：

Jason Penny 也有 written 一个 SQL 函数，用于将 UTF-8 转换为 Unicode（MIT 许可证），它为我提供了一个简单的示例：

CREATE FUNCTION dbo.UTF8_TO_NVARCHAR(@in VarChar(MAX))
   RETURNS NVarChar(MAX)
AS
BEGIN
   DECLARE @out NVarChar(MAX), @i int, @c int, @c2 int, @c3 int, @nc int

   SELECT @i = 1, @out = ''

   WHILE (@i <= Len(@in))
   BEGIN
      SET @c = Ascii(SubString(@in, @i, 1))

      IF (@c < 128)
      BEGIN
         SET @nc = @c
         SET @i = @i + 1
      END
      ELSE IF (@c > 191 AND @c < 224)
      BEGIN
         SET @c2 = Ascii(SubString(@in, @i + 1, 1))

         SET @nc = (((@c & 31) * 64 /* << 6 */) | (@c2 & 63))
         SET @i = @i + 2
      END
      ELSE
      BEGIN
         SET @c2 = Ascii(SubString(@in, @i + 1, 1))
         SET @c3 = Ascii(SubString(@in, @i + 2, 1))

         SET @nc = (((@c & 15) * 4096 /* << 12 */) | ((@c2 & 63) * 64 /* << 6 */) | (@c3 & 63))
         SET @i = @i + 3
      END

      SET @out = @out + NChar(@nc)
   END
   RETURN @out
END
GO

安东尼打勾的答案“看起来”对我来说更好，但如果进行转换并调查任何差异，可能会同时运行？！

我们还使用下面的 very 丑陋代码来检测 BMP 页面 unicode 字符，这些字符被编码为 UTF-8，然后从 varchar 转换为 nvarchar 字段，可以转换为 UCS-16。

LIKE (N'%[' + CONVERT(NVARCHAR,(CHAR(192))) + CONVERT(NVARCHAR,(CHAR(193))) + CONVERT(NVARCHAR,(CHAR(194))) + CONVERT(NVARCHAR,(CHAR(195))) + CONVERT(NVARCHAR,(CHAR(196))) + CONVERT(NVARCHAR,(CHAR(197))) + CONVERT(NVARCHAR,(CHAR(198))) + CONVERT(NVARCHAR,(CHAR(199))) + CONVERT(NVARCHAR,(CHAR(200))) + CONVERT(NVARCHAR,(CHAR(201))) + CONVERT(NVARCHAR,(CHAR(202))) + CONVERT(NVARCHAR,(CHAR(203))) + CONVERT(NVARCHAR,(CHAR(204))) + CONVERT(NVARCHAR,(CHAR(205))) + CONVERT(NVARCHAR,(CHAR(206))) + CONVERT(NVARCHAR,(CHAR(207))) + CONVERT(NVARCHAR,(CHAR(208))) + CONVERT(NVARCHAR,(CHAR(209))) + CONVERT(NVARCHAR,(CHAR(210))) + CONVERT(NVARCHAR,(CHAR(211))) + CONVERT(NVARCHAR,(CHAR(212))) + CONVERT(NVARCHAR,(CHAR(213))) + CONVERT(NVARCHAR,(CHAR(214))) + CONVERT(NVARCHAR,(CHAR(215))) + CONVERT(NVARCHAR,(CHAR(216))) + CONVERT(NVARCHAR,(CHAR(217))) + CONVERT(NVARCHAR,(CHAR(218))) + CONVERT(NVARCHAR,(CHAR(219))) + CONVERT(NVARCHAR,(CHAR(220))) + CONVERT(NVARCHAR,(CHAR(221))) + CONVERT(NVARCHAR,(CHAR(222))) + CONVERT(NVARCHAR,(CHAR(223))) + CONVERT(NVARCHAR,(CHAR(224))) + CONVERT(NVARCHAR,(CHAR(225))) + CONVERT(NVARCHAR,(CHAR(226))) + CONVERT(NVARCHAR,(CHAR(227))) + CONVERT(NVARCHAR,(CHAR(228))) + CONVERT(NVARCHAR,(CHAR(229))) + CONVERT(NVARCHAR,(CHAR(230))) + CONVERT(NVARCHAR,(CHAR(231))) + CONVERT(NVARCHAR,(CHAR(232))) + CONVERT(NVARCHAR,(CHAR(233))) + CONVERT(NVARCHAR,(CHAR(234))) + CONVERT(NVARCHAR,(CHAR(235))) + CONVERT(NVARCHAR,(CHAR(236))) + CONVERT(NVARCHAR,(CHAR(237))) + CONVERT(NVARCHAR,(CHAR(238))) + CONVERT(NVARCHAR,(CHAR(239)))
    + N'][' + CONVERT(NVARCHAR,(CHAR(128))) + CONVERT(NVARCHAR,(CHAR(129))) + CONVERT(NVARCHAR,(CHAR(130))) + CONVERT(NVARCHAR,(CHAR(131))) + CONVERT(NVARCHAR,(CHAR(132))) + CONVERT(NVARCHAR,(CHAR(133))) + CONVERT(NVARCHAR,(CHAR(134))) + CONVERT(NVARCHAR,(CHAR(135))) + CONVERT(NVARCHAR,(CHAR(136))) + CONVERT(NVARCHAR,(CHAR(137))) + CONVERT(NVARCHAR,(CHAR(138))) + CONVERT(NVARCHAR,(CHAR(139))) + CONVERT(NVARCHAR,(CHAR(140))) + CONVERT(NVARCHAR,(CHAR(141))) + CONVERT(NVARCHAR,(CHAR(142))) + CONVERT(NVARCHAR,(CHAR(143))) + CONVERT(NVARCHAR,(CHAR(144))) + CONVERT(NVARCHAR,(CHAR(145))) + CONVERT(NVARCHAR,(CHAR(146))) + CONVERT(NVARCHAR,(CHAR(147))) + CONVERT(NVARCHAR,(CHAR(148))) + CONVERT(NVARCHAR,(CHAR(149))) + CONVERT(NVARCHAR,(CHAR(150))) + CONVERT(NVARCHAR,(CHAR(151))) + CONVERT(NVARCHAR,(CHAR(152))) + CONVERT(NVARCHAR,(CHAR(153))) + CONVERT(NVARCHAR,(CHAR(154))) + CONVERT(NVARCHAR,(CHAR(155))) + CONVERT(NVARCHAR,(CHAR(156))) + CONVERT(NVARCHAR,(CHAR(157))) + CONVERT(NVARCHAR,(CHAR(158))) + CONVERT(NVARCHAR,(CHAR(159))) + CONVERT(NVARCHAR,(CHAR(160))) + CONVERT(NVARCHAR,(CHAR(161))) + CONVERT(NVARCHAR,(CHAR(162))) + CONVERT(NVARCHAR,(CHAR(163))) + CONVERT(NVARCHAR,(CHAR(164))) + CONVERT(NVARCHAR,(CHAR(165))) + CONVERT(NVARCHAR,(CHAR(166))) + CONVERT(NVARCHAR,(CHAR(167))) + CONVERT(NVARCHAR,(CHAR(168))) + CONVERT(NVARCHAR,(CHAR(169))) + CONVERT(NVARCHAR,(CHAR(170))) + CONVERT(NVARCHAR,(CHAR(171))) + CONVERT(NVARCHAR,(CHAR(172))) + CONVERT(NVARCHAR,(CHAR(173))) + CONVERT(NVARCHAR,(CHAR(174))) + CONVERT(NVARCHAR,(CHAR(175))) + CONVERT(NVARCHAR,(CHAR(176))) + CONVERT(NVARCHAR,(CHAR(177))) + CONVERT(NVARCHAR,(CHAR(178))) + CONVERT(NVARCHAR,(CHAR(179))) + CONVERT(NVARCHAR,(CHAR(180))) + CONVERT(NVARCHAR,(CHAR(181))) + CONVERT(NVARCHAR,(CHAR(182))) + CONVERT(NVARCHAR,(CHAR(183))) + CONVERT(NVARCHAR,(CHAR(184))) + CONVERT(NVARCHAR,(CHAR(185))) + CONVERT(NVARCHAR,(CHAR(186))) + CONVERT(NVARCHAR,(CHAR(187))) + CONVERT(NVARCHAR,(CHAR(188))) + CONVERT(NVARCHAR,(CHAR(189))) + CONVERT(NVARCHAR,(CHAR(190))) + CONVERT(NVARCHAR,(CHAR(191)))
    + N']%') COLLATE Latin1_General_BIN

以上：

检测编码U+0080到U+FFFF的多字节序列（U+0080到U+07FF编码为110xxxxx 10xxxxxx，U+0800到U+FFFF编码为1110xxxx 10xxxxxx 10xxxxxx）
即它检测十六进制字节 0xC0 到 0xEF，后跟十六进制字节 0x80 到 0xBF
忽略 ASCII 控制字符 U+0000 到 U+001F
忽略已正确编码为 unicode >= U+0100（即不是 UTF-8）的字符
忽略 unicode 字符 U+0080 到 U+00FF 如果它们看起来不是 UTF-8 序列的一部分，例如“合作”。
不使用 LIKE "%[X-Y]" 表示 X=0x80 到 Y=0xBF，因为可能存在排序规则问题
使用 CONVERT(VARCHAR,CHAR(X)) 而不是 NCHAR，因为我们遇到了将 NCHAR 转换为错误值（对于某些值）的问题。
忽略大于 U+FFFF 的 UTF 字符（4 到 6 个字节序列，其第一个字节为十六进制 0xF0 到 0xFD）

【讨论】：

这个对我有用，与安东尼·福尔的回答相反，事实并非如此。谢谢@robocat

【解决方案3】：

我添加了一些修改以使用新的字符串聚合函数 string_agg，来自 sql server 2017 和 2019

SELECT @result=STRING_AGG(NCHAR([codepoint]),'') WITHIN GROUP (ORDER BY position ASC) 
FROM codepoints

将 de @result 部分更改为这个。 XML 仍然以老式方式工作。在 2019 年，string_agg 的运行速度比 xml 版本快得多（显然...... string_agg 现在是原生的，比较不公平）

【讨论】：

【解决方案4】：

我通过结合来自@robocat 的答案、更多案例与来自https://github.com/benkasminbullock/unicode-c/blob/master/unicode.c 的逻辑以及对来自@ 的扩展unicode 字符编码问题的解决方案，制作了一个解决方案，该解决方案还可以处理4 字节序列（如表情符号） 987654322@。它不快也不漂亮，但无论如何它对我有用。这个特殊的解决方案在它找到未知字节的任何地方都包括 Unicode 替换字符。在这些情况下，最好只抛出异常，或者保留字节原样，因为将来的编码可能会关闭，但我更喜欢在我的用例中这样做。

-- Started with https://stackoverflow.com/questions/28168055/convert-text-value-in-sql-server-from-utf8-to-iso-8859-1
-- Modified following source in https://github.com/benkasminbullock/unicode-c/blob/master/unicode.c
-- Made characters > 65535 work using https://dba.stackexchange.com/questions/139551/how-do-i-set-a-sql-server-unicode-nvarchar-string-to-an-emoji-or-supplementary
CREATE FUNCTION dbo.UTF8_TO_NVARCHAR(@in VarChar(MAX)) RETURNS NVarChar(MAX) AS
BEGIN
    DECLARE @out NVarChar(MAX), @thisOut NVARCHAR(MAX), @i int, @c int, @c2 int, @c3 int, @c4 int

    SELECT @i = 1, @out = ''

    WHILE (@i <= Len(@in)) BEGIN
        SET @c = Ascii(SubString(@in, @i, 1))

        IF @c <= 0x7F BEGIN
            SET @thisOut = NCHAR(@c)
            SET @i = @i + 1
        END
        ELSE IF @c BETWEEN 0xC2 AND 0xDF BEGIN
            SET @c2 = Ascii(SubString(@in, @i + 1, 1))
            IF @c2 < 0x80 OR @c2 > 0xBF BEGIN
                SET @thisOut = NCHAR(0xFFFD)
                SET @i = @i + 1
            END
            ELSE BEGIN
                SET @thisOut = NCHAR(((@c & 31) * 64 /* << 6 */) | (@c2 & 63))
                SET @i = @i + 2
            END
        END
        ELSE IF @c BETWEEN 0xE0 AND 0xEF BEGIN
            SET @c2 = Ascii(SubString(@in, @i + 1, 1))
            SET @c3 = Ascii(SubString(@in, @i + 2, 1))
            IF @c2 < 0x80 OR @c2 > 0xBF OR @c3 < 0x80 OR (@c = 0xE0 AND @c2 < 0xA0) BEGIN
                SET @thisOut = NCHAR(0xFFFD)
                SET @i = @i + 1
            END
            ELSE BEGIN
                SET @thisOut = NCHAR(((@c & 15) * 4096 /* << 12 */) | ((@c2 & 63) * 64 /* << 6 */) | (@c3 & 63))
                SET @i = @i + 3
            END
        END
        ELSE IF @c BETWEEN 0xF0 AND 0xF4 BEGIN
            SET @c2 = Ascii(SubString(@in, @i + 1, 1))
            SET @c3 = Ascii(SubString(@in, @i + 2, 1))
            SET @c4 = Ascii(SubString(@in, @i + 3, 1))
            IF @c2 < 0x80 OR @c2 >= 0xC0 OR @c3 < 0x80 OR @c3 >= 0xC0 OR @c4 < 0x80 OR @c4 >= 0xC0 OR (@c = 0xF0 AND @c2 < 0x90) BEGIN
                SET @thisOut = NCHAR(0xFFFD)
                SET @i = @i + 1
            END
            ELSE BEGIN
                DECLARE @nc INT = (((@c & 0x07) * 262144 /* << 18 */) | ((@c2 & 0x3F) * 4096 /* << 12 */) | ((@c3 & 0x3F) * 64) | (@c4 & 0x3F))
                DECLARE @HighSurrogateInt INT = 55232 + (@nc / 1024), @LowSurrogateInt INT = 56320 + (@nc % 1024)
                SET @thisOut = NCHAR(@HighSurrogateInt) + NCHAR(@LowSurrogateInt)
                SET @i = @i + 4
            END
        END
        ELSE BEGIN
            SET @thisOut = NCHAR(0xFFFD)
            SET @i = @i + 1
        END

        SET @out = @out + @thisOut
    END
    RETURN @out
END
GO

【讨论】：

【解决方案5】：

这是我为 SQL Server 2017 编写的作为内联表值函数 (TVF) 的版本。它限制为 4000 字节的输入字符串，因为这足以满足我的需要。限制输入大小并写入 TVF 使得这个版本比迄今为止发布的缩放器值函数快得多。它还通过输出替换字符来处理无法在 UCS-2 字符串中表示的四字节 UTF-8 序列（例如由表情符号创建的序列）。

CREATE OR ALTER FUNCTION [dbo].[fnUTF8Decode](@UTF8 VARCHAR(4001)) RETURNS TABLE AS RETURN

/*  Converts a UTF-8 encoded VARCHAR to NVARCHAR (UCS-2).  Based on UTF-8 documentation on Wikipedia and the 
    code/discussion at https://stackoverflow.com/a/31064459/1979220.
    
    One can quickly detect strings that need conversion using the following expression:

        <FIELD> LIKE CONCAT('%[', CHAR(192), '-', CHAR(255), ']%') COLLATE Latin1_General_BIN. 

    Be aware, however, that this may return true for strings that this function has already converted to UCS-2.
    See robocat's answer on the above referenced Stack Overflow thread for a slower but more robust expression.

    Notes/Limitations

    1)  Written as a inline table-valued function for optimized performance.  
    
    2)  Only tested on a database with SQL_Latin1_General_CP1_CI_AS collation.  More specifically, this was
        not designed to output Supplementary Characters and converts all such UTF-8 sequences to �.

    3)  Empty input strings, '', and strings with nothing but invalid UTF-8 chars are returned as NULL.

    4)  Assumes input is UTF-8 compliant.  For example, extended ASCII characters such as en dash CHAR(150)
        are not allowed unless part of a multi-byte sequence and will be skipped otherwise.  In other words:
            
            SELECT * FROM dbo.fnUTF8Decode(CHAR(150)) -> NULL
    
    5)  Input should be limited to 4000 characters to ensure that output will fit in NVARCHAR(4000), which is
        what STRING_AGG outputs when fed a sequence of NVARCHAR(1) characters generated by NCHAR.  However,
        T-SQL silently truncates overlong parameters so we've declared our input as VARCHAR(4001) to allow 
        STRING_AGG to generate an error on overlong input.  If we didn't do this, callers would never be
        notified about truncation.

    6)  If we need to process more than 4000 chars in the future, we'll need to change input to VARCHAR(MAX) and 
        CAST the CASE WHEN expression to NVARCHAR(MAX) to force STRING_AGG to output NVARCHAR(MAX).  Note that
        this change will significantly degrade performance, which is why we didn't do it in the first place.

    7)  Due to use of STRING_AGG, this is only compatible with SQL 2017.  It will probably work fine on 2019
        but that version has native UTF-8 support so you're probably better off using that.  For earlier versions,
        replace STRING_AGG with a CLR equivalent (ms-sql-server-group-concat-sqlclr) or FOR XML PATH(''), TYPE...
*/
SELECT      STRING_AGG (
                CASE 
                    WHEN A1 & 0xF0 = 0xF0 THEN  --Four byte sequences (like emoji) can't be represented in UCS-2
                        NCHAR(0xFFFD)           --Output U+FFFD (Replacement Character) instead
                    WHEN A1 & 0xE0 = 0xE0 THEN  --Three byte sequence; get/combine relevant bits from A1-A3
                        NCHAR((A1 & 0x0F) * 4096 | (A2 & 0x3F) * 64 | (A3 & 0x3F))
                    WHEN A1 & 0xC0 = 0xC0 THEN  --Two byte sequence; get/combine relevant bits from A1-A2
                        NCHAR((A1 & 0x3F) * 64 | (A2 & 0x3F))
                    ELSE NCHAR(A1)              --Regular ASCII character; output as is
                END
            , '') UCS2
FROM        dbo.fnNumbers(ISNULL(DATALENGTH(@UTF8), 0))
CROSS APPLY (SELECT ASCII(SUBSTRING(@UTF8, I, 1)) A1, ASCII(SUBSTRING(@UTF8, I + 1, 1)) A2, ASCII(SUBSTRING(@UTF8, I + 2, 1)) A3) A
WHERE       A1 <= 127 OR A1 >= 192              --Output only ASCII chars and one char for each multi-byte sequence
GO

请注意，以上需要“数字”表或生成器函数。这是我使用的函数：

CREATE OR ALTER FUNCTION [dbo].[fnNumbers](@MaxNumber BIGINT) RETURNS TABLE AS RETURN

/*  Generates a table of numbers up to the specified @MaxNumber, limited to 4,294,967,296.  Useful for special case
    situations and algorithms.  Copied from https://www.itprotoday.com/sql-server/virtual-auxiliary-table-numbers
    with minor formatting and name changes.
*/

WITH L0 AS (
    SELECT 1 I UNION ALL SELECT 1           --Generates 2 rows
), L1 AS (
    SELECT 1 I FROM L0 CROSS JOIN L0 L      --          4 rows
), L2 AS (
    SELECT 1 I FROM L1 CROSS JOIN L1 L      --          16 rows
), L3 AS (
    SELECT 1 I FROM L2 CROSS JOIN L2 L      --          256 rows
), L4 AS (
    SELECT 1 I FROM L3 CROSS JOIN L3 L      --          65,536 rows
), L5 AS (
    SELECT 1 I FROM L4 CROSS JOIN L4 L      --          4,294,967,296 rows
), Numbers AS (
    SELECT ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) I FROM L5
)
SELECT TOP (@MaxNumber) I FROM Numbers ORDER BY I
GO

【讨论】：

【解决方案6】：

我刚刚成功地创建了一个新字段作为 varchar(255) 并将新字段设置为旧字段 nvarchar(255)。这就产生了国际化的“美国化”版本。

更新世界城市设置 admin_correct = admin_name

 varchar(255)     nvarchar(255)

【讨论】：

【解决方案7】：

我找到了我需要做的查询，只是还没有编码。

ALTER TABLE dbo.MyTable ALTER COLUMN CharCol
        varchar(10)COLLATE Latin1_General_CI_AS NOT NULL;

【讨论】：