CREATE TABLE "singles_18_12_6" (
  "outcome" text,
  "date" text,
  "tournament" text,
  "surface" text,
  "opponent" text,
  "score" text
);

Question: When the surface is clay, and the tournament of barcelona what is the score?
SQL: SELECT "score" FROM "singles_18_12_6" WHERE "surface"='clay' AND "tournament"='barcelona';

Question: What was the surface when the opponent was judith wiesner, and the outcome was winner?
SQL: SELECT "surface" FROM "singles_18_12_6" WHERE "outcome"='winner' AND "opponent"='judith wiesner';

Question: What is the opponent for the tournament of rio de janeiro?
SQL: SELECT "opponent" FROM "singles_18_12_6" WHERE "tournament"='rio de janeiro';

Question: What is the opponent with the outcome of runner-up with a date of 19 september 1994?
SQL: SELECT "opponent" FROM "singles_18_12_6" WHERE "outcome"='runner-up' AND "date"='19 september 1994';

Question: What was the opponent for the tournament of taranto?
SQL: SELECT "opponent" FROM "singles_18_12_6" WHERE "tournament"='taranto';