Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_19 ( area__km²_ INTEGER, density___km²_ VARCHAR, official_website VARCHAR )

### Question ###
What is the sum of the area values for districts having density over 462 and websites of http://krishna.nic.in/?

### Accurate SQL ###

SELECT SUM(area__km²_) FROM table_name_19 WHERE density___km²_ > 462 AND official_website = "http://krishna.nic.in/"