Change forum post author

It is not possible to change without deleting the original author and reassigning to the other author.

There are also no functionality to transfer content from one user to another, is it correct?

There is not, you could however delete the post and recreate it impersonating the correct user if it's a one off.

Unfortunately - it is non one off. 

We want to move forum posts and media uploads made by multiple employees under the single  shared "company" Community user.

I know that you guys do not recommend this, but is there any way to achieve it via SQL script directly in DB?  

Unfortunately - it is non one off. 

We want to move forum posts and media uploads made by multiple employees under the single  shared "company" Community user.

I know that you guys do not recommend this, but is there any way to achieve it via SQL script directly in DB?