Table schema:
CREATE TABLE CLASS (crs_code VARCHAR); CREATE TABLE course (dept_code VARCHAR, crs_credit INTEGER, crs_code VARCHAR)

Question: Find the total credits of all classes offered by each department.
SQL: SELECT SUM(T1.crs_credit), T1.dept_code FROM course AS T1 JOIN CLASS AS T2 ON T1.crs_code = T2.crs_code GROUP BY T1.dept_code