SQL Retrieve info from two tables

I am really lost with sql.. i tried to read everything but no luck.

I have two tables and need to retrieve data from them:

First Table – Workers | Second Table – Stores

+--------+------------+-----------+
| 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    |  |
+--------+---------+--+

Select workers first name that belong to more than one store?

Select all workers first name that are in the shoe store?

Hope you can help me.

Thanks

Answer

Select workers first name that belong to more than one store

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

Select all workers first name that are in the shoe store

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