Please list the coach IDs who received the award twice from 1970 to 1990.
from 1970 to 1990 refers to year between 1970 and 1990;  received award twice refers to coachID where Count(coachID) = 2
SELECT coachID FROM awards_coaches WHERE year BETWEEN 1970 AND 1990 GROUP BY coachID, award HAVING COUNT(award) = 2