我想找出飞行员的平均工资和包括飞行员在内的员工的平均工资之间的差异,所以基本上是一个(平均(飞行员) - 平均(员工))。
虽然我在将两个 SQL 查询组合在一起时遇到了问题,但到目前为止我已经设法做到了:
SELECT AVG(salary) AS 'average(pilot)'
FROM employees e, certified c
WHERE e.EID IN (SELECT EID FROM certified GROUP BY eid);
SELECT AVG(salary) AS 'average(employees)'
FROM employees e, certified c
WHERE e.EID NOT IN (SELECT EID FROM certified GROUP BY eid);
现在我只需要从第一个查询中减去第二个查询的结果。我该如何进行?
最佳答案
select (select query2) - (select query1);
我想这应该可行,
select (select avg(salary) as 'average(employees)'
from employees e, certified c
where e.EID not in (select EID from certified group by eid)) - (select avg(salary) as 'average(pilot)'
from employees e, certified c
where e.EID in (select EID from certified group by eid));
引用this类似的答案
关于mysql - 从第二个查询的平均值中减去第一个查询的平均值,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/52688256/