SQL从两个表中检索信息

Question

我真的迷失了sql。我试图阅读所有内容，但没有运气。

我有两个表，需要从它们中检索数据：

第一张表-工人|第二张表-商店

+--------+------------+-----------+
| Worker | First_Name | Last_name |
+--------+------------+-----------+
|     10 | John       | Smith     |
|     20 | Robert     | Henry     |
|    100 | Jessica    | Bailey    |
|    120 | Kelly      | Bates     |
+--------+------------+-----------+

+--------+---------+--+
| Worker |  Store  |  |
+--------+---------+--+
|     10 | Shoe    |  |
|     20 | Clothes |  |
|    100 | Shoe    |  |
|    120 | HR      |  |
|    120 | Shoe    |  |
+--------+---------+--+

选择属于多个商店的工人名字吗？

选择所有在鞋店工作的工人的名字吗？

希望你能帮助我。

谢谢

Answer 1

选择属于多个商店的工人名字

select Workers.First_Name
from Workers
join Stores on Stores.Worker = Workers.Worker
group by Workers.First_name
having count(*) > 1

选择所有在鞋店里的工人名字

select Workers.First_Name
from Workers
join Stores on Stores.Worker = Workers.Worker
where Stores.Store = 'Shoe'