CREATE TABLE table_name_11 (week NUMBER, game_site VARCHAR2, date VARCHAR2)

What average week has shea stadium as the game site, and 1979-12-09 as the date?
SELECT AVG(week) FROM table_name_11 WHERE game_site = "shea stadium" AND date = "1979-12-09"
SELECT AVG("week") FROM "table_name_11" WHERE "1979-12-09" = "date" AND "game_site" = "shea stadium"