Find out schema/table with Sqlmap

I am trying to figuring out the schema/table of a particular website, but not sure if it is possible, think of the following scenario:

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https://preview.redd.it/viddwnx6nak41.jpg?width=274&format=pjpg&auto=webp&s=367f9bf7a269d5f6192472adce9345697f792113

Let's say the log in page is in "example.com/login". The parameters are user and password. Supposedly there suppose to be a database.

How can I run an sqlmap on this url to know the schema/tables if there is no '.php' neither '?'. Every tutorial I checked had brought examples with '.php' urls, which in my case there isn't.

What else could be done? (In preference with sqlmap)

Thanks in advance!

Ps. It is a specific website which I can legally do that.