CREATE TABLE table_6415 ("Rank" FLOAT, "Airport" TEXT, "Code  ( IATA/ICAO ) " TEXT, "Total Cargo  ( Metric Tonnes ) " FLOAT, "% Change" TEXT)

What is the highest rank for the airport with a code of HKG/VHHH?
SELECT MAX("Rank") FROM table_6415 WHERE "Code (IATA/ICAO)" = 'hkg/vhhh'
SELECT MAX("Rank") FROM "table_6415" WHERE "Code (IATA/ICAO)" = 'hkg/vhhh'