CREATE TABLE "previous_winners" (
  "year" real,
  "mens_singles" text,
  "womens_singles" text,
  "mens_doubles" text,
  "womens_doubles" text,
  "mixed_doubles" text
);

Question: Who won the mens singles when sayaka sato won the womens singles?
SQL: SELECT "mens_singles" FROM "previous_winners" WHERE "womens_singles"='Sayaka Sato';