如何使用SQL在单列中获取逗号分隔的值

Question

I have the below table and expected result. Please let me know if it is possible to achieve the result. Please refer the picture attached.

Answer 1

You can use listagg() :

select e.id, e.name, e.sal,
       listagg(d.dept, ',') within group (order by d.dept_id) as depts,
       listagg(d.dept_id, ',') within group (order by d.dept_id) as dept_ids,
from employee e left join
     department d
     on e.name = d.name
group by e.id, e.name, e.sal;

Some comments on the data model.

• Your department table should have a dept_id that is the primary key (no duplicates).
• Your table that is called department should really be called employee_departments because it is a junction table, combining two different entities.
• This table should be using emp_id as the link to employee , not name . That is, the foreign key relationship should be to the primary key of employee .