Quick! What's the difference between SPARQL 1.1 Protocol and SPARQL 1.1 Query Protocol? How does SPARQL 1.1 Update relate to it, and what role does an entailment regime play in it? What is SPARQL-Star and how is it different from RDF-Star or Turtle-Star?
(SPARQL is genuinely a lot nicer than SQL to work with, but you sure wouldn't know it from the absolute rat's nest of almost-but-not-quite-the-same specifications!)