CREATE TABLE table_79821 ("Sydney" TEXT, "Melbourne" TEXT, "Perth" TEXT, "Adelaide" TEXT, "Gold Coast" TEXT, "Auckland" TEXT)

what is the Sydney that has Adelaide, Gold Coast, Melbourne, and Auckland are all yes?
SELECT "Sydney" FROM table_79821 WHERE "Adelaide" = 'yes' AND "Gold Coast" = 'yes' AND "Melbourne" = 'yes' AND "Auckland" = 'yes'
SELECT "Sydney" FROM "table_79821" WHERE "Adelaide" = 'yes' AND "Auckland" = 'yes' AND "Gold Coast" = 'yes' AND "Melbourne" = 'yes'