CREATE TABLE student (stu_num NUMBER, stu_lname CLOB, stu_fname CLOB, stu_init CLOB, stu_dob TIME, stu_hrs NUMBER, stu_class CLOB, stu_gpa NUMBER, stu_transfer NUMBER, dept_code CLOB, stu_phone CLOB, prof_num NUMBER)
CREATE TABLE employee (emp_num NUMBER, emp_lname CLOB, emp_fname CLOB, emp_initial CLOB, emp_jobcode CLOB, emp_hiredate TIME, emp_dob TIME)
CREATE TABLE course (crs_code CLOB, dept_code CLOB, crs_description CLOB, crs_credit NUMBER)
CREATE TABLE enroll (class_code CLOB, stu_num NUMBER, enroll_grade CLOB)
CREATE TABLE professor (emp_num NUMBER, dept_code CLOB, prof_office CLOB, prof_extension CLOB, prof_high_degree CLOB)
CREATE TABLE department (dept_code CLOB, dept_name CLOB, school_code CLOB, emp_num NUMBER, dept_address CLOB, dept_extension CLOB)
CREATE TABLE class (class_code CLOB, crs_code CLOB, class_section CLOB, class_time CLOB, class_room CLOB, prof_num NUMBER)

What are the first names of all history professors who do not teach?
SELECT T1.emp_fname FROM employee AS T1 JOIN professor AS T2 ON T1.emp_num = T2.emp_num JOIN department AS T3 ON T2.dept_code = T3.dept_code WHERE T3.dept_name = 'History' EXCEPT SELECT T4.emp_fname FROM employee AS T4 JOIN class AS T5 ON T4.emp_num = T5.prof_num
SELECT "T1"."emp_fname" FROM "employee" "T1" JOIN "professor" "T2" ON "T1"."emp_num" = "T2"."emp_num" JOIN "department" "T3" ON "T2"."dept_code" = "T3"."dept_code" AND "T3"."dept_name" = 'History' EXCEPT SELECT "T4"."emp_fname" FROM "employee" "T4" JOIN "class" "T5" ON "T4"."emp_num" = "T5"."prof_num"