Question: In which women's doubles did Wang Junjie play men's singles?
SQL: SELECT "Women's doubles" FROM "2-12163879-1" WHERE "Men's singles" = 'Wang Junjie';

Question: In what mixed doubles did Niels Christian Kaldau play in men's singles?
SQL: SELECT "Mixed doubles" FROM "2-12163879-1" WHERE "Men's singles" = 'Niels Christian Kaldau';

Question: Which mixed doubles happened later than 2011?
SQL: SELECT "Mixed doubles" FROM "2-12163879-1" WHERE "Year" > 2011.0;