统计每个部门中人数（ ）
A.select sum(id) from emp group by deptno B.select sum(id) from emp order by deptno C.select count(id) from emp order by deptno D.select count(id) from emp group by deptno正确答案D
统计每个部门中人数（ ）
A.select sum(id) from emp group by deptno B.select sum(id) from emp order by deptno C.select count(id) from emp order by deptno D.select count(id) from emp group by deptno正确答案D
