[taspeotis]

> It's not about indexing paths you indicate, XML databases are about indexing the whole structure

From my first link, MSSQL does both:

    The primary XML index indexes all tags, values, and paths within the XML instances in an XML column
    ...
    To enhance search performance, you can create secondary XML indexes. A primary XML index must first exist before you can create secondary indexes

And it supports some reasonable subset of XQuery [1].

[1] http://technet.microsoft.com/en-us/library/ms187854.aspx