What is the diameter for 1997 when longitude is 212.0e and latitude is 47.0n?
CREATE TABLE "dorsa" (
  "name" text,
  "latitude" text,
  "longitude" text,
  "diameter_km" real,
  "year_named" real
);
SELECT MIN("diameter_km") FROM "dorsa" WHERE "year_named"=1997 AND "longitude"='212.0e' AND "latitude"='47.0n';