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

Question: Which men's singles has a women's singles of marketa koudelková as well as a Men's doubles of jan lanik / pavel weigner??
SQL: SELECT "men_s_singles" FROM "junior_champions" WHERE "women_s_singles"='marketa koudelková' AND "men_s_doubles"='jan lanik / pavel weigner';

Question: Which men's singles had a women's doubles team of irena ferencová / yweta trminková?
SQL: SELECT "men_s_singles" FROM "junior_champions" WHERE "women_s_doubles"='irena ferencová / yweta trminková';

Question: What is the mean year when the women's doubles team was helena turcinková / buresová?
SQL: SELECT AVG("year") FROM "junior_champions" WHERE "women_s_doubles"='helena turcinková / buresová';