But being the SQL Server 2005 fanatic that I am, I couldn’t help but notice he didn’t give the product any love. So for those you using (or will soon be using) SQL Server 2005 and XQuery, I’m happy to present this quick guide to XQuery, SQL Server 2005 style.

What is XQuery for? Like T-SQL is a query language over data stored in tables, XQuery is a query language over XML instances. The key difference is that instead of returning a set of fields in a row, XQuery returns a sequence of nodes. The primary use case of XQuery in SQL Server 2005 is to extract some portion of a given number of XML nodes from stored set of XML instances. You might to do something simple like get a list of the values in the nodes conforming to a given XPath expression, or you might want to do something more complex, like transform a set of XML nodes into a new XML instance. Normally, you’ll be doing these operations to return data to a client or high-tier service or object. Of course, since we’re storing them these XML instances in a database, it is likely that we’ll be doing Data Manipulation Language (DML) operations like inserting, updating and deleting nodes as well. As XQuery stands today, there are not specific operations for DML. Microsoft has added them using a new and unique to SQL Server concept called XML DML. To save time and space, I won’t be covering XML DML in this posting.