Question

在oracle SQL中如何列出在同一部门工作的员工对...我的员工表如下：

employeeid  department
    101        2
    102        2
    103        3
    104        3
    105        4

Answer 1

您可以通过

获得拥有多名员工的部门的所有员工

SELECT * FROM employees
WHERE department IN
(
  SELECT department
  FROM employees
  GROUP BY department
  HAVING COUNT(*) > 1
)

或使用LISTAGG在列表中显示ID：

  SELECT 
    department,
    LISTAGG(employeeid, ', ') AS EmployeeList
  FROM employees
  GROUP BY department
  HAVING COUNT(*) > 1

Answer 2

如果您的表名为t，则可以“列出”在同一部门中使用自联接工作的员工对，如下所示：

select t1.employeeid as employee1, t2.employeeid as employee2, department
from t t1 join t t2 using (department)
where t1.employeeid < t2.employeeid

公平警告：对于拥有大量员工的部门，对的数量渐渐增长，就像该部门员工人数的平方的1/2倍，因此您可能会获得大量的行数。真正的“输入表。

如果需要，您可以根据需要对结果进行排序，例如添加以下行：

order by department, employee1, employee2