CREATE TABLE "buller_district" (
  "name" text,
  "years" text,
  "area" text,
  "authority" text,
  "decile" real,
  "roll" real
);

Question: What is the average roll of a school with state authority and a decile of 9?
SQL: SELECT AVG("roll") FROM "buller_district" WHERE "authority"='state' AND "decile"=9;

Question: Which area has state authority and a roll fewer than 18?
SQL: SELECT "area" FROM "buller_district" WHERE "authority"='state' AND "roll"<18;

Question: What is the roll for the school with state authority and a decile of 9?
SQL: SELECT "roll" FROM "buller_district" WHERE "authority"='state' AND "decile"=9;

Question: What is the average decile of Westport South School?
SQL: SELECT AVG("decile") FROM "buller_district" WHERE "name"='westport south school';