mysql - 查找至少有 2 名员工的部门

Question

我需要生成 sql 问题，该问题将显示所有部门中至少有 2 个人。

SELECT department.name
FROM department
INNER JOIN employee
ON department.id = employee.department_id
GROUP BY employee.id
HAVING COUNT(employee.id) >= 2;

它没有向我显示此查询的任何内容

Answer 1

我认为您在错误的列上使用了 GROUP BY。
如果你想统计每个部门的员工，那么你需要GROUP BY department.id。

SELECT department.id, department.name, COUNT(employee.id) AS total_employee
FROM department
INNER JOIN employee
ON department.id = employee.department_id
GROUP BY department.id, department.name
HAVING COUNT(employee.id) >= 2;