CREATE TABLE table_28138035_26 (mens_singles VARCHAR2, womens_singles VARCHAR2)

Who won the mens singles when lau sui fei won the womens singles?
SELECT mens_singles FROM table_28138035_26 WHERE womens_singles = "Lau Sui Fei"
SELECT "mens_singles" FROM "table_28138035_26" WHERE "Lau Sui Fei" = "womens_singles"