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

Question: WHAT ARE THE NAMES OF THE MENS DOUBLES WHEN THE WOMENS DOUBLES WAS PIRET HAMER HELEN REINO?
SQL: SELECT "mens_doubles" FROM "past_winners" WHERE "womens_doubles"='Piret Hamer Helen Reino';

Question: WHAT IS THE NAME OF THE MENS DOUBLES PLAYER WHEN THE WOMENS DOUBLES PLAYER IS HELEN REINO KAI-RIIN SALUSTE?
SQL: SELECT "mens_doubles" FROM "past_winners" WHERE "womens_doubles"='Helen Reino Kai-Riin Saluste';

Question: WHAT IS THE NAME OF THE MIXED DOUBLES PLAYER WHEN THE WOMENS SINGLE PLAYER IS KAIRI VIILUP?
SQL: SELECT "mixed_doubles" FROM "past_winners" WHERE "womens_singles"='Kairi Viilup';

Question: HOW MANY YEARS DID MENS DOUBLES PLAYER HEIKI SORGE MEELIS MAISTE PLAY?
SQL: SELECT COUNT("year") FROM "past_winners" WHERE "mens_doubles"='Heiki Sorge Meelis Maiste';