Table: melanie_oudin_match
Columns: date
tournament
surface
opponent
score

Question: Which opponent was on July 21, 2008?
SQL: SELECT "opponent" FROM melanie_oudin_match WHERE "date" = 'july 21, 2008'

Question: What was the date of the tournament with a clay surface and an opponent of Irina Falconi?
SQL: SELECT "date" FROM melanie_oudin_match WHERE "surface" = 'clay' AND "opponent" = 'irina falconi'

Question: Who was the opponent on May 10, 2009?
SQL: SELECT "opponent" FROM melanie_oudin_match WHERE "date" = 'may 10, 2009'