Question: Which unique cities are in Asian countries where Chinese is the official language ?
SQL: SELECT DISTINCT t3.name FROM country AS t1 JOIN countrylanguage AS t2 ON t1.code = t2.countrycode JOIN city AS t3 ON t1.code = t3.countrycode WHERE t2.isofficial = 't' AND t2.language = 'chinese' AND t1.continent = "asia"