CREATE TABLE "wta_tour_venues" (
  "rank" text,
  "stadium" text,
  "capacity" real,
  "city" text,
  "country" text,
  "tournament_hosted" text
);

Question: What country has grandstand stadium as the stadium?
SQL: SELECT "country" FROM "wta_tour_venues" WHERE "stadium"='grandstand stadium';

Question: What is the average capacity that has switzerland as the country?
SQL: SELECT AVG("capacity") FROM "wta_tour_venues" WHERE "country"='switzerland';

Question: What is the average capacity that has rod laver arena as the stadium?
SQL: SELECT AVG("capacity") FROM "wta_tour_venues" WHERE "stadium"='rod laver arena';