Table: eduardo_schwank_matches
Columns: date
tournament
surface
opponent
score

Question: Which tournament did the opponent Guillermo Carry play?
SQL: SELECT "tournament" FROM eduardo_schwank_matches WHERE "opponent" = 'guillermo carry'

Question: Who was the opponent on April 21, 2008?
SQL: SELECT "opponent" FROM eduardo_schwank_matches WHERE "date" = 'april 21, 2008'

Question: Who is the opponent on November 22, 2009, clay surface?
SQL: SELECT "opponent" FROM eduardo_schwank_matches WHERE "surface" = 'clay' AND "date" = 'november 22, 2009'