If you enable warehouse management on a site with existing location, you would need to delete all internal locations related to this site and recreate them under the correct warehouse. This imply you have no stock.

At least I would advise you to take the training to understand the various setup this will enable. What do you expect from warehouse management?

Is there training available on Sage U? I haven't seen anything really for the WRH features.  I wasn't sure what to expect, I wanted to see what features could benefit my company.  

Could just updating the WRH field in the location tables using SQL work with a warehouse that is created under the site ? 

Is there training available on Sage U? I haven't seen anything really for the WRH features.  I wasn't sure what to expect, I wanted to see what features could benefit my company.  

Could just updating the WRH field in the location tables using SQL work with a warehouse that is created under the site ? 

I guess there used to be eLearning session on sageu about it. But it was for Version 7 release (so many years ago). The best would be now to request a ILT training to cover this topic. 

Updating the tables using SQL could irredeemably corrupt the database so I strongly recommend you not to. I would never dared doing it.

To identify if this would be useful or not, can you describe what are the benefits you would expect from it? What is your current stock organization?