SQL查询以查找共享完全相同的一组值的对 [英] SQL query for finding pairs that share the exact same set of values

问题描述

我无法针对此问题生成查询.

I'm having trouble generating a query for this problem.

我有这个小桌子

Tasks(employee_name, task)

Sample Data:
Tasks
------------------
Joe | taskA
Joe | taskB
Ted | taskA
Jim | taskB
Ray | taskA
Ray | taskB
John| taskA
Tim | taskC

我需要找到任务完全相同的所有员工对.

I need to find all pairs of employees that have the exact same tasks.

例如，使用结果集上方的数据应为:

For example using the data above the result set should be:

---------------------
employee1 | employee2
---------------------
  Joe     | Ray
  Ted     | John

我正在使用mySQL作为数据库. 谢谢！

I'm using mySQL for the database. Thanks!

推荐答案

select a.employee_name,b.employee_name
from tasks as a, tasks as b
where a.employee_name>b.employee_name
group by a.employee_name,b.employee_name
having group_concat(distinct a.task order by a.task)=group_concat(distinct b.task order by b.task)

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