Table: yrd_data
Columns: city
hanzi
hanyu_pinyin
regional_population_2010
gdp_2011_billion_yuan

Question: Which Hanyu Pinyin has a GDP in 2011 larger than 688.02 billion yuan and a regional population of 8,700,400 in 2010?
SQL: SELECT "hanyu_pinyin" FROM yrd_data WHERE "gdp_2011_billion_yuan" > 688.02 AND "regional_population_2010" = '8,700,400'

Question: Which Hanzi has a Regional Population of 4,591,972 in 2010?
SQL: SELECT "hanzi" FROM yrd_data WHERE "regional_population_2010" = '4,591,972'