CREATE TABLE "previous_winners" (
  "year" text,
  "men_s_singles" text,
  "women_s_singles" text,
  "men_s_doubles" text,
  "women_s_doubles" text,
  "mixed_doubles" text
);

Question: What year did Carolina Marin win the Women's singles?
SQL: SELECT "year" FROM "previous_winners" WHERE "women_s_singles"='carolina marin';

Question: Who won the Mixed Doubles in 2007?
SQL: SELECT "mixed_doubles" FROM "previous_winners" WHERE "year"='2007';

Question: Who won the Mixed doubles when Juliane Schenk won the Women's Singles?
SQL: SELECT "mixed_doubles" FROM "previous_winners" WHERE "women_s_singles"='juliane schenk';