也可以对单个查询使用union。

select lt.name from location l join sales_person as lt on l.location_to = lt.id
UNION ALL
select lf.name from location l join sales_person as lf on l.location_from = lf.id

加入 sales_person 两张table location 为…取名字 location_to 以及 location_from ```
select t.name,f.name
from location l
join sales_person t on l.location_to = t.id
join sales_person f on l.location_from = f.id

我想你有 `name` 列中的 `sales_person` table