Sql-server – How to escape XML characters in TSQL before converting to XML

sql servert-sqltype conversionxml

I have XML structure which is input param for my stored procedure. It contains element with & (which is escaped in XML). When I extract that element to VARCHAR I receive & which is not valid XML character. I need to escape it, before converting to XML again. How to do that without REPLACE?

I have the following text: param1=xyz&para2=dasdasdfdas&param3. It is a part of query string. I converted it to XML and send it as a part of XML structure:

<zzz xmlns="http://example.com">

Inside the stored procedure I need to extract it. I do that with:

ISNULL(NULLIF(LTRIM(RTRIM(@XMLInput.value('declare default element namespace "http://example.com"; (zzz/bbb)[1]', 'NVARCHAR(250)'))), ''), '');

I after that the value contains normal text (&-s are not escaped – &).

After some processing I need to put that string inside other XML. I make:

CAST( ... AS XML);

Because &-s are not escaped I got error.

Best Answer

Use for xml path to create XML instead of casting.

select @YourVariable for xml path(''), type

Empty string in the path expression and the absence of an alias on the returned column will give you your string back as xml.