Docker容器在本地连接到MySQL数据库 - >重定向到另一个容器

I am new to Docker.

I have read that it is better to keep an app per container.

I need to run web app (LAMP stack). So I have found the container for running PHP + Apache.

Now I need to set up a mysql container. But I am not sure what is the correct way to do that.

I read that it is possible to connect multiple containers together.

The idea is to make it trasnparent to the container running PHP + Apache when it tries to connect to mysql database locally.

But redirect all local connections to another container.

Another idea I have is to provide environment variable with host where should all connections go. In this case I need to have publicly accessible mysql server, but I need to keep it private and accessible only locally.

Could you please suggest a better option to choose in my case ?

Thank you