CREATE TABLE department (dept_name VARCHAR, dept_code VARCHAR)
CREATE TABLE student (stu_gpa INT, dept_code VARCHAR)

What is the name and the average gpa of department whose students have the highest average gpa?
SELECT T2.dept_name, AVG(T1.stu_gpa) FROM student AS T1 JOIN department AS T2 ON T1.dept_code = T2.dept_code GROUP BY T1.dept_code ORDER BY AVG(T1.stu_gpa) DESC LIMIT 1
SELECT "T2"."dept_name", AVG("T1"."stu_gpa") FROM "student" AS "T1" JOIN "department" AS "T2" ON "T1"."dept_code" = "T2"."dept_code" GROUP BY "T1"."dept_code" ORDER BY AVG("T1"."stu_gpa") DESC NULLS LAST LIMIT 1