select distinct job_id,department_id from job_history order by department_id;
select distinct department_id,job_id from job_history order by department_id;
请问这两句有什么区别?下面是执行结果,为什么执行的结果是一样的?JOB_ID DEPARTMENT_ID
---------- ----------------------
MK_REP 20
ST_CLERK 50
IT_PROG 60
SA_MAN 80
SA_REP 80
AC_ACCOUNT 90
AD_ASST 90
AD_PRES 90
AC_ACCOUNT 110
AC_MGR 110 10 所选行DEPARTMENT_ID JOB_ID
---------------------- ----------
20 MK_REP
50 ST_CLERK
60 IT_PROG
80 SA_MAN
80 SA_REP
90 AC_ACCOUNT
90 AD_ASST
90 AD_PRES
110 AC_ACCOUNT
110 AC_MGR 10 所选行
select distinct department_id,job_id from job_history order by department_id;
请问这两句有什么区别?下面是执行结果,为什么执行的结果是一样的?JOB_ID DEPARTMENT_ID
---------- ----------------------
MK_REP 20
ST_CLERK 50
IT_PROG 60
SA_MAN 80
SA_REP 80
AC_ACCOUNT 90
AD_ASST 90
AD_PRES 90
AC_ACCOUNT 110
AC_MGR 110 10 所选行DEPARTMENT_ID JOB_ID
---------------------- ----------
20 MK_REP
50 ST_CLERK
60 IT_PROG
80 SA_MAN
80 SA_REP
90 AC_ACCOUNT
90 AD_ASST
90 AD_PRES
110 AC_ACCOUNT
110 AC_MGR 10 所选行
没区别 都是去掉 job_id,department_id的重复 不就是求部门的工种
就是结果显示列名位置的区别
distinct就是去掉job_id和department_id重复的,只剩下一条数据