How much Snatch has a Total (kg) smaller than 257?
CREATE TABLE "middleweight_77_kg" (
  "name" text,
  "bodyweight" real,
  "snatch" real,
  "clean_jerk" real,
  "total_kg" real
);
SELECT SUM("snatch") FROM "middleweight_77_kg" WHERE "total_kg"<257;