CREATE TABLE table_name_6 (floors NUMBER, name VARCHAR2, rank VARCHAR2, year VARCHAR2)

What is the average amount of floors of the building that is ranked larger than 30, a year prior to 1977 and an address of 100 Van Ness Avenue?
SELECT AVG(floors) FROM table_name_6 WHERE rank > 30 AND year < 1977 AND name = "100 van ness avenue"
SELECT AVG("floors") FROM "table_name_6" WHERE "100 van ness avenue" = "name" AND "rank" > 30 AND "year" < 1977