Concrete is porous and this is going to be a challenge.
You might be able to use a sander on it, and this is going to be messy. If you can move this table outside, it would be best.
If not, I would have someone use a shop vac next to the sander and cover everything else.
I would definitely put two full coats of sealer on it, when you’re finished with the restoration.
Concrete stains so easily. Try going over the entire table with soft scrub using a scrubby. Don't just focus on spot need to basically stain the entire top to lessen the stain. Once it's cleaned be sure to seal.
Ummm, water is clear and shouldn’t stain concrete.
Hope this helps. :)
Hoping this post will have some great tips for you.