I want the lowest points diff for against being less than 578 and lost being 15 and points more than 26
CREATE TABLE "table" (
  "team" text,
  "played" real,
  "drawn" real,
  "lost" real,
  "against" real,
  "points_diff" real,
  "points" real
);
SELECT MIN("points_diff") FROM "table" WHERE "against"<578 AND "lost"=15 AND "points">26;