Question: Each physical user will have about 20 tables in the database.

When a new user registers, another 20 tables will be created with access only for their new MySQL account.

Data does not have to be shared between users.

Is this logic more secure than simply having just 20 tables for all the users?
And what about performance will be dead or not ?

**EDIT**

I just want to be sure that a user who likes to "play" with injections and finds a way around will not be able to access other user data.

Answer: 
I'm not exactly sure what you mean, but yes. The output of a properly written hash function should be the same regardless of language.

The only difference between the hashes of different programming languages libraries and on different platforms will be speed. Although in properly written libraries - the difference will be trivial.
It will always be the same if you're not using a salt. If you're using a salt then it will be different if you change the salt.