CREATE TABLE table_23397386_2 (rank__timeslot_ VARCHAR, airdate VARCHAR)

How many rankings (timeslot) were there for the episode that aired on May 2, 2010?
SELECT COUNT(rank__timeslot_) FROM table_23397386_2 WHERE airdate = "May 2, 2010"
SELECT COUNT("rank__timeslot_") FROM "table_23397386_2" WHERE "May 2, 2010" = "airdate"