For my own edification, what is the goal of SPARQL compared to normal SQL or if you live in predicate-land, Prolog or Datalog? The semantic web tools never see

For my own edification, what is the goal of SPARQL compared to normal SQL or if you live in predicate-land, Prolog or Datalog? The semantic web tools never seemed to have their breakout moment and seem to run in parallel to "mainstream" history of relational and logic programming, but I've never really understood why.