On Transact SQL language the XML is an xml data type and can store xml instances in a column, or a variable of xml type.

XML syntax:

xml ( [ CONTENT | DOCUMENT ] xml_schema_collection )

XML example:

USE model;
GO
DECLARE @xml AS xml;
SELECT @xml =
(
SELECT
CONCAT (id, ', ',name, ', ',price)
FROM courses
WHERE id=3
);
SELECT @xml;
GO

USE model;
GO
DECLARE @xmlDoc xml
SET @xmlDoc =
(SELECT id, Name
FROM courses
FOR XML AUTO, TYPE)
SELECT @xmlDoc
GO