human
Considering the provided database schema and associated query, produce SQL code to retrieve the answer to the query. 
###Database Schema: Code, District, Headquarters, Population (2011), Area (km²), Density (/km²), Official website
###Question: What is the sum of the area values for districts having density over 462 and websites of http://krishna.nic.in/?
gpt
SELECT SUM Area (km²) FROM table WHERE Density (/km²) > 462 AND Official website = http://krishna.nic.in/