How to get data from db on remote site using php?

Question

PHP

On an external site there is a form for entering data. The form has one field for entering a number and one button. The request is sent to the database.
Will it be possible to get a response from the database from an external site if the request to the form is made by a POST request $content = curl(' ya.ru ','username=alex&password=qwerty')?

Answer 1

If, during the normal operation of the site, sending data after writing to the database returns something:
That is, you will get what is displayed after submitting the form.
*** If this kind of action is not conceived by the system, then this is a security hole.