CREATE TABLE "classification" (
  "driver" text,
  "constructor" text,
  "laps" real,
  "time_retired" text,
  "grid" real
);

Question: what is the least laps when the driver is rolf stommelen and the grid is more than 18?
SQL: SELECT MIN("laps") FROM "classification" WHERE "driver"='rolf stommelen' AND "grid">18;

Question: what is the most laps with a grid of 20?
SQL: SELECT MAX("laps") FROM "classification" WHERE "grid"=20;