Name the date for clay surface and location of santos, brazil
CREATE TABLE "singles_finals_19_8_11" (
  "outcome" text,
  "date" text,
  "location" text,
  "surface" text,
  "opponent_in_final" text,
  "score" text
);
SELECT "date" FROM "singles_finals_19_8_11" WHERE "surface"='clay' AND "location"='santos, brazil';