Can i use two different user tables for on WP install?

Well, it’s not going to work because you won’t always have the post value on each page (only when they have just logged in).
So as soon as wp serves up the next page it won’t have a the POST variable anymore.

Why do you feel a need to do this? (Personally I cannot think of a good reason)

If they need different capabilties, then
You could simply create additional roles

If it is simply for reporting, then categorise users in some other way with a custom meta field.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)