sql查询以显示部门名称、位置名称、员工人数

这是我的密码：

SELECT dname,loc,avg(sal)
FROM dept,emp
GROUP BY loc;

我想写一个查询来显示部门名称、位置、员工人数以及该部门所有员工的平均工资。在dname、loc、雇员人数和Avgsalary列上贴上标签

数据如下：

DNAME          LOC           Number of People     Salary                        
-------------- ------------- ---------------- ----------                        
SALES          CHICAGO                      6    1566.67                        
RESEARCH       DALLAS                       5       2175                        
ACCOUNTING     NEW YORK                     3    2916.67              

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您只是在选择列表中遗漏了SUM（1），而您的分组成员在该问题上可能是错误的：

select dname as DNAME, loc as LOC, SUM(1) as Number_of_People, avg(sal) as AvgSalary from dept,emp group by dname, loc;

--无需求和（1）使用计数（e.deptno）计算人数--

select d.dname as DNAME, d.loc as LOC, count(e.deptno)as "Number of people", round(avg(e.sal),2) as "Salary" from dept d, emp e where d.deptno = e.deptno group by d.dname, d.loc, e.deptno;