SQL Server：替换 VARCHAR(MAX) 字段中的无效 XML 字符
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SQL Server: Replace invalid XML characters from a VARCHAR(MAX) field
提问by Sathish
I have a VARCHAR(MAX)field which is being interfaced to an external system in XMLformat. The following errors were thrown by the interface:
我有一个VARCHAR(MAX)以XML格式与外部系统接口的字段。接口抛出以下错误：
mywebsite.com-2015-0202.xml:413005: parser error : xmlParseCharRef: invalid xmlChar value 29
ne and Luke's family in Santa Fe. You know you have a standing invitation,
^
mywebsite.com-2015-0202.xml:455971: parser error : xmlParseCharRef: invalid xmlChar value 25
The apprentice nodded, because frankly, who hadnt? That diseases like chol
^
mywebsite.com.com-2015-0202.xml:456077: parser error : xmlParseCharRef: invalid xmlChar value 28
bon mot; a sentimental love of nature and animals; the proverbial British 
^
mywebsite.com-2015-0202.xml:472073: parser error : xmlParseCharRef: invalid xmlChar value 20
"Andyou want that?"
^
mywebsite.com-2015-0202.xml:492912: parser error : xmlParseCharRef: invalid xmlChar value 25
She couldnt live like this anymore.
We found that the following list of characters are invalid:
我们发现以下字符列表无效：
�








	
























I am trying to clean this data, and I found a SQL function to clean these characters here. However, the function was taking NVARCHAR(4000)as input parameter, so I have changed the function to use VARCHAR(MAX)instead.
我正在尝试清理这些数据，我在这里找到了一个 SQL 函数来清理这些字符。但是，该函数将NVARCHAR(4000)作为输入参数，因此我已更改要使用的函数VARCHAR(MAX)。
Could anyone please advise if changing the NVARCHAR(4000)to VARCHAR(MAX)would produce wrong results? Sorry, I wouldn't be able to test this interface locally so thought to seek opinion/advise.
任何人都可以请告知如果更改NVARCHAR(4000)toVARCHAR(MAX)会产生错误的结果吗？抱歉，我无法在本地测试此界面，因此想寻求意见/建议。
Original Function:
原始功能：
CREATE FUNCTION fnStripLowAscii (@InputString nvarchar(4000))
RETURNS nvarchar(4000)
AS
BEGIN
IF @InputString IS NOT NULL
BEGIN
DECLARE @Counter int, @TestString nvarchar(40)
SET @TestString = '%[' + NCHAR(0) + NCHAR(1) + NCHAR(2) + NCHAR(3) + NCHAR(4) + NCHAR(5) + NCHAR(6) + NCHAR(7) + NCHAR(8) + NCHAR(11) + NCHAR(12) + NCHAR(14) + NCHAR(15) + NCHAR(16) + NCHAR(17) + NCHAR(18) + NCHAR(19) + NCHAR(20) + NCHAR(21) + NCHAR(22) + NCHAR(23) + NCHAR(24) + NCHAR(25) + NCHAR(26) + NCHAR(27) + NCHAR(28) + NCHAR(29) + NCHAR(30) + NCHAR(31) + ']%'
SELECT @Counter = PATINDEX (@TestString, @InputString COLLATE Latin1_General_BIN)
WHILE @Counter <> 0
BEGIN
SELECT @InputString = STUFF(@InputString, @Counter, 1, NCHAR(164))
SELECT @Counter = PATINDEX (@TestString, @InputString COLLATE Latin1_General_BIN)
END
END
RETURN(@InputString)
END
Modified Version:
修改版本：
CREATE FUNCTION [dbo].RemoveInvalidXMLCharacters (@InputString VARCHAR(MAX))
RETURNS VARCHAR(MAX)
AS
BEGIN
IF @InputString IS NOT NULL
BEGIN
DECLARE @Counter INT, @TestString NVARCHAR(40)
SET @TestString = '%[' + NCHAR(0) + NCHAR(1) + NCHAR(2) + NCHAR(3) + NCHAR(4) + NCHAR(5) + NCHAR(6) + NCHAR(7) + NCHAR(8) + NCHAR(11) + NCHAR(12) + NCHAR(14) + NCHAR(15) + NCHAR(16) + NCHAR(17) + NCHAR(18) + NCHAR(19) + NCHAR(20) + NCHAR(21) + NCHAR(22) + NCHAR(23) + NCHAR(24) + NCHAR(25) + NCHAR(26) + NCHAR(27) + NCHAR(28) + NCHAR(29) + NCHAR(30) + NCHAR(31) + ']%'
SELECT @Counter = PATINDEX (@TestString, @InputString COLLATE Latin1_General_BIN)
WHILE @Counter <> 0
BEGIN
SELECT @InputString = STUFF(@InputString, @Counter, 1, ' ')
SELECT @Counter = PATINDEX (@TestString, @InputString COLLATE Latin1_General_BIN)
END
END
RETURN(@InputString)
END
采纳答案by Sathish
It is safe to use VARCHAR(MAX)as my data column is a VARCHAR(MAX)field. Also, there will be an overhead of converting VARCHAR(MAX)to NVARCHAR(MAX)if I pass a VARCHAR(MAX)field to the SQL function which accepts the NVARCHAR(MAX)param.
可以安全使用，VARCHAR(MAX)因为我的数据列是一个VARCHAR(MAX)字段。此外，如果我将一个字段传递给接受该参数的 SQL 函数，那么将产生转换VARCHAR(MAX)为的开销。NVARCHAR(MAX)VARCHAR(MAX)NVARCHAR(MAX)
Thank you very much @RhysJones, @Damien_The_Unbeliever for your comments.
非常感谢@RhysJones、@Damien_The_Unbeliever 的评论。
回答by Shnugo
There is a trick using the implicit conversion of VARBINARYto base64 and back:
有一个使用隐式转换VARBINARY到 base64 并返回的技巧：
Here your list of evil
这是你的邪恶清单
DECLARE @evilChars VARCHAR(MAX)=
CHAR(0x0)
+ CHAR(0x1)
+ CHAR(0x2)
+ CHAR(0x3)
+ CHAR(0x4)
+ CHAR(0x5)
+ CHAR(0x6)
+ CHAR(0x7)
+ CHAR(0x8)
+ CHAR(0x9)
+ CHAR(0xa)
+ CHAR(0xb)
+ CHAR(0xc)
+ CHAR(0xd)
+ CHAR(0xe)
+ CHAR(0xf)
+ CHAR(0x10)
+ CHAR(0x11)
+ CHAR(0x12)
+ CHAR(0x13)
+ CHAR(0x14)
+ CHAR(0x15)
+ CHAR(0x16)
+ CHAR(0x17)
+ CHAR(0x18)
+ CHAR(0x19)
+ CHAR(0x1a)
+ CHAR(0x1b)
+ CHAR(0x1c)
+ CHAR(0x1d)
+ CHAR(0x1e)
+ CHAR(0x1f)
+ CHAR(0x7f);
This works
这有效
DECLARE @XmlAsString NVARCHAR(MAX)=
(
SELECT @evilChars FOR XML PATH('test')
);
SELECT @XmlAsString;
The result (some are "printed")
结果（有些是“打印”的）
<test>�

</test>
The following is forbidden
禁止以下行为
SELECT CAST(@XmlAsString AS XML)
But you can use the implicit conversion of VARBINARY to base64
但是你可以使用 VARBINARY 到 base64 的隐式转换
DECLARE @base64 NVARCHAR(MAX)=
(
SELECT CAST(@evilChars AS VARBINARY(MAX)) FOR XML PATH('test')
);
SELECT @base64;
The result
结果
<test>AAECAwQFBgcICQoLDA0ODxAREhMUFRYXGBkaGxwdHh9/</test>
Now you've got your real XML including the special characters!
现在您已经获得了真正的 XML，包括特殊字符！
SELECT CAST(CAST(@base64 AS XML).value('/test[1]','varbinary(max)') AS VARCHAR(MAX)) FOR XML PATH('reconverted')
The result
结果
<reconverted>�

</reconverted>
回答by Rhys Jones
You need to use nvarchar(max)instead of varchar(max)but otherwise the change is fine.
您需要使用nvarchar(max)而不是，varchar(max)否则更改就可以了。
