Table: bitburger_open_tennis_2
Columns: year
men_s_singles
women_s_singles
men_s_doubles
women_s_doubles
mixed_doubles

Question: What is the year in which Yong Yudianto won the men's singles?
SQL: SELECT MIN("year") FROM bitburger_open_tennis_2 WHERE "men_s_singles" = 'yong yudianto'

Question: Who won the men's singles in 1999?
SQL: SELECT "men_s_singles" FROM bitburger_open_tennis_2 WHERE "year" = 1999