The resolve-uri function takes a relative URI as its first argument and resolves it against the base URI in the second argument. The result is of data type xs:string. The function's implementation treats both inputs as strings; no checks are performed as to whether the resources identified by these URIs actually exist.
XQuery, XSLT 2.0, XSLT 3.0.
The relative URI to be resolved against the base.
The base URI.
In the mapping illustrated below, the first argument provides the relative URI MyFile.html, and the second argument provides the base URI file:///C:/Dir/. The resolved URI will be a concatenation of both, so file:///C:/Dir/MyFile.html.