142 ST_CLERK 143 ST_CLERK 144 ST_CLERK 149 SA_MAN 174 SA_REP 176 SA_REP Was a Sales Representative 176 SA_MAN Became a Sales Manager 176 SA_REP Went back to a Sales Rep 178 SA_REP 200 AD_ASST Looks like the same here 200 AD_ASST 200 AC_ACCOUNT 201 MK_REP 201 MK_MAN 202 MK_REP 205 AC_MGR 206 AC_ACCOUNT 30 rows selected Change the code and add in DEPARTMENT_ID SELECT employee_id, job_id, department_id FROM employees UNION SELECT employee_id, job_id, department_id FROM job_history ORDER BY employee_id; What was the result? How many duplicates, if any? Why?
142 ST_CLERK 143 ST_CLERK 144 ST_CLERK 149 SA_MAN 174 SA_REP 176 SA_REP Was a Sales Representative 176 SA_MAN Became a Sales Manager 176 SA_REP Went back to a Sales Rep 178 SA_REP 200 AD_ASST Looks like the same here 200 AD_ASST 200 AC_ACCOUNT 201 MK_REP 201 MK_MAN 202 MK_REP 205 AC_MGR 206 AC_ACCOUNT 30 rows selected Change the code and add in DEPARTMENT_ID SELECT employee_id, job_id, department_id FROM employees UNION SELECT employee_id, job_id, department_id FROM job_history ORDER BY employee_id; What was the result? How many duplicates, if any? Why?