How to compare two MySql databases?

Question

MySQL

There are two databases (mySql), in theory identical, but the 1st app crashes (with a very strange error, not about mysql at all, it’s useful to debug, an hour later I decided that it was probably easier to compare). I want to find differences. What's the easiest way?
win10 openserver mysql5.6

Answer 1

found some hell of a mess. In php addslashes, I replaced NULL with "" As a result, a very non-obvious error.
I compared it like this: I
made two dimps, threw it into phpStorm, compared it using the history of file changes.
How did you not guess right away? HZ. Thanks to everyone who tried to help.

Answer 2

Check for the presence of keys in tables.