Table: atp_match_stats
Columns: aces
player
opponent
round
year
event
surface
sets

Question: What is the event year radek štěpánek was the round and there were less than 3 aces?
SQL: SELECT COUNT("event") FROM atp_match_stats WHERE "round" = 'radek štěpánek' AND "aces" < 3

Question: How many players were in the event after 2011 with less than 9 aces?
SQL: SELECT COUNT("player") FROM atp_match_stats WHERE "event" > 2011 AND "aces" < 9

Question: Who was the opponent in the 2011 event with less than 113 players?
SQL: SELECT "opponent" FROM atp_match_stats WHERE "player" < 113 AND "event" = 2011

Question: What is the highest number of players during 1r year with a clay set and more than 4 aces?
SQL: SELECT MAX("player") FROM atp_match_stats WHERE "year" = '1r' AND "sets" = 'clay' AND "aces" > 4