Which director had the most popular film from 1937 to 1990?
from 1937 to 1990 refers to substr(release_date, length(release_date) - 3, length(release_date)) between '1937' and '1990'; the most popular film refers to movie_title where MAX(total_gross);
SELECT T2.director FROM characters AS T1 INNER JOIN director AS T2 ON T1.movie_title = T2.name INNER JOIN movies_total_gross AS T3 ON T3.movie_title = T1.movie_title WHERE SUBSTR(T3.release_date, LENGTH(T3.release_date) - 3, LENGTH(T3.release_date)) BETWEEN '1937' AND '1990' ORDER BY CAST(REPLACE(trim(T3.total_gross, '$'), ',', '') AS REAL) DESC LIMIT 1