CREATE TABLE table_15984957_2 (oilers_first_downs VARCHAR2, date VARCHAR2)

On Sept. 17, how many first downs did the oilers have?
SELECT COUNT(oilers_first_downs) FROM table_15984957_2 WHERE date = "Sept. 17"
SELECT COUNT("oilers_first_downs") FROM "table_15984957_2" WHERE "Sept. 17" = "date"