Table: greek_tennis_stats
Columns: year
men_s_singles
women_s_singles
men_s_doubles
women_s_doubles
mixed_doubles

Question: What is the year when Conrad Hückstädt won Men's Single?
SQL: SELECT "year" FROM greek_tennis_stats WHERE "men_s_singles" = 'conrad hückstädt'

Question: Who won the Men's Double the same year as Florentina Petre winning the Women's Singles?
SQL: SELECT "men_s_doubles" FROM greek_tennis_stats WHERE "women_s_singles" = 'florentina petre'

Question: In what year was there no competition for women?
SQL: SELECT "year" FROM greek_tennis_stats WHERE "women_s_singles" = 'no competition'