关于group by 分组函数控制台显示优化

若group分组项为XXX，break on XXX skip number，可将分组项只显示为一个名称，其他为空
*注意语法问题：*group by 分组函数若select查询中有col项，则by后必须有相同的col项除聚合函数项除外，
例如：

--sal select语句中出现sal，group up无，错误
select dname,ename,sal from empinfo group by rollup(dname,ename);
-- select语句中出现sal，但为聚合函数，正确
select dname,ename,sum(sal) from empinfo group by rollup(dname,ename);

实例：

--查询同一部门下各种工作的总薪水
SQL> break on deptno skip 2
SQL> select deptno,job,sum(sal) from emp group by rollup(deptno,job);

    DEPTNO JOB         SUM(SAL)
---------- --------- ----------
        10 CLERK           1300
           MANAGER         2450
           PRESIDENT       5000
                           8750


        20 CLERK           1900
           ANALYST         6000
           MANAGER         2975
                          10875


    DEPTNO JOB         SUM(SAL)
---------- --------- ----------

        30 CLERK            950
           MANAGER         2850
           SALESMAN        5600
                           9400


                          29025



已选择13行。
--按部门名称分组
SQL> select dname,ename,sum(sal) from empinfo group by rollup (dname,ename);

DNAME          ENAME        SUM(SAL)
-------------- ---------- ----------
SALES          WARD             1250
SALES          ALLEN            1600
SALES          BLAKE            2850
SALES          JAMES             950
SALES          MARTIN           1250
SALES          TURNER           1500
SALES                           9400
RESEARCH       FORD             3000
RESEARCH       ADAMS            1100
RESEARCH       JONES            2975
RESEARCH       SCOTT            3000

DNAME          ENAME        SUM(SAL)
-------------- ---------- ----------
RESEARCH       SMITH             800
RESEARCH                       10875
ACCOUNTING     KING             5000
ACCOUNTING     CLARK            2450
ACCOUNTING     MILLER           1300
ACCOUNTING                      8750
                               29025

已选择18行。
SQL> break on dname skip 2
SQL> select dname,ename,sum(sal) from empinfo group by rollup (dname,ename);

DNAME          ENAME        SUM(SAL)
-------------- ---------- ----------
SALES          WARD             1250
               ALLEN            1600
               BLAKE            2850
               JAMES             950
               MARTIN           1250
               TURNER           1500
                                9400


RESEARCH       FORD             3000
               ADAMS            1100

DNAME          ENAME        SUM(SAL)
-------------- ---------- ----------
RESEARCH       JONES            2975
               SCOTT            3000
               SMITH             800
                               10875


ACCOUNTING     KING             5000
               CLARK            2450
               MILLER           1300
                                8750


DNAME          ENAME        SUM(SAL)
-------------- ---------- ----------

                               29025