使用limit仅返回查询的顶部结果：

SELECT 
    FORMAT(SUM(e.salary),0) as sumOfSalary, 
    d.departName 
FROM
    employee e 
JOIN depart d 
    on (d.id = e.depart) 
GROUP BY d.departName
ORDER BY sumOfSalary desc
LIMIT 1

当您使用格式时，结果不是按数字值排序的，而是按字母顺序排列的，所以“600”按降序排在“3000”之前

select departName, format(max(sumOfSalary),0) from 
 (SELECT 
    SUM(e.salary) as sumOfSalary, 
    d.departName 
    FROM
    employee e 
    JOIN depart d on (d.id = e.depart) 
    GROUP BY d.departName
    ORDER BY SUM(e.salary) desc limit 1) as nested

如果你只需要所有部门中的最高工资（我希望我正确地回答了你的问题！），然后使用嵌套查询：

SELECT FORMAT(MAX(sumOfSalary),0) FROM (
SELECT 
SUM(e.salary) as sumOfSalary, d.departName 
FROM employee e 
JOIN depart d on d.id = e.depart)
GROUP BY d.departName
) AS ss