What engine has the Mercedes AMG Petronas f1 team, and 93 points?
CREATE TABLE "complete_formula_one_results" (
  "year" real,
  "entrant" text,
  "chassis" text,
  "engine" text,
  "points" text
);
SELECT "engine" FROM "complete_formula_one_results" WHERE "entrant"='mercedes amg petronas f1 team' AND "points"='93';