What is the total roll with a decile less than 7, and an authority of state, in the Macraes Flat area?
CREATE TABLE "waitaki_district" (
  "name" text,
  "years" text,
  "gender" text,
  "area" text,
  "authority" text,
  "decile" real,
  "roll" real
);
SELECT COUNT("roll") FROM "waitaki_district" WHERE "decile"=7 AND "authority"='state' AND "area"='macraes flat';