MR的案例：求每個部門的工資總額

MR的案例：求每個部門的工資總額 1、表：員工表emp        SQL: select deptno,sum(sal) from emp group by deptno; DEPTNO   SUM(SAL) ---------- ---------- 30       9400 20      10875 10       8750 2、開發MR實現 [[email protected] t

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