I installed the full version of Knime 2.12.0, and I selected all the available sites, plus I added the "trunk" site. Then, I also checked for updates.
But I cannot find the SPARQL Node neither among installed nodes nor among the ones available for installation. I do search for "sparql" in the install knime extensions window without results.
the SPARQL nodes are part of the EU-OPENSCREEN plugin which is part of the stable community contributions. For details about the installation have a look at the community page.
With the next KNIME release in July we will also release a lot of new Semantic Web nodes including a SPARQL query node in the KNIME Labs section. So stay tuned.