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

Question: What is the women's singles before 1965 with kaj lindfors ann-louise von essen being mixed doubles?
SQL: SELECT "women_s_singles" FROM "past_winners" WHERE "year"<1965 AND "mixed_doubles"='kaj lindfors ann-louise von essen';

Question: When did mika heinonen susanna dahlberg win mixed doubles?
SQL: SELECT AVG("year") FROM "past_winners" WHERE "mixed_doubles"='mika heinonen susanna dahlberg';

Question: How many years did pia pajunen nina sundberg win women's doubles?
SQL: SELECT COUNT("year") FROM "past_winners" WHERE "women_s_doubles"='pia pajunen nina sundberg';

Question: Who won women's singles in 1961?
SQL: SELECT "women_s_singles" FROM "past_winners" WHERE "year"=1961;