SQL Server 2005 T-SQL 中的 Base64 编码 [英] Base64 encoding in SQL Server 2005 T-SQL

问题描述

我想编写一个 T-SQL 查询，其中我将一个字符串编码为 Base64 字符串.令人惊讶的是，我找不到任何用于进行 Base64 编码的本机 T-SQL 函数.是否存在本机功能?如果没有，在 T-SQL 中进行 Base64 编码的最佳方法是什么?

I'd like to write a T-SQL query where I encode a string as a Base64 string. Surprisingly, I can't find any native T-SQL functions for doing Base64 encoding. Does a native function exist? If not, what's the best way to do Base64 encoding in T-SQL?

推荐答案

我知道这已经得到了回答，但我只是花了更多的时间来想出单行 SQL 语句来完成这个，所以我将在此处分享，以防其他人需要这样做:

I know this has already been answered, but I just spent more time than I care to admit coming up with single-line SQL statements to accomplish this, so I'll share them here in case anyone else needs to do the same:

-- Encode the string "TestData" in Base64 to get "VGVzdERhdGE="
SELECT
    CAST(N'' AS XML).value(
          'xs:base64Binary(xs:hexBinary(sql:column("bin")))'
        , 'VARCHAR(MAX)'
    )   Base64Encoding
FROM (
    SELECT CAST('TestData' AS VARBINARY(MAX)) AS bin
) AS bin_sql_server_temp;

-- Decode the Base64-encoded string "VGVzdERhdGE=" to get back "TestData"
SELECT 
    CAST(
        CAST(N'' AS XML).value(
            'xs:base64Binary("VGVzdERhdGE=")'
          , 'VARBINARY(MAX)'
        ) 
        AS VARCHAR(MAX)
    )   ASCIIEncoding
;

我不得不在第一个(编码)查询中使用子查询生成的表，因为我找不到任何方法将原始值(TestData")转换为其十六进制字符串表示(5465737444617461")以包含为XQuery 语句中 xs:hexBinary() 的参数.

I had to use a subquery-generated table in the first (encoding) query because I couldn't find any way to convert the original value ("TestData") to its hex string representation ("5465737444617461") to include as the argument to xs:hexBinary() in the XQuery statement.

我希望这对某人有所帮助！

I hope this helps someone!

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