Looking for some advice for storing multiple users in a column

Hi,

I’m looking for some advice on how to handle this best, I’ve tried a few ways, but I’m really not convinced they will work or are the best way to handle this.

Essentially, I have a MySQL table with multiple rows of categories, for each row, there is an “Assigned” column. I want to store the security identities of multiple people in this column, so they can then be retrieved for use later to check if they are assigned to that category.

What is the best way of me going about this? The row needs to work in such a way where I can retrieve each user from it individually, and remove/add users individually as needed (while keeping the other users in it). You can also add a category from inside the web app.

I was originally thinking of an array, but this doesn’t seem all that suitable for this instance, seeing as categories can be dynamically added.