It's a good practice to create a user account with absolutely minimal permissions. Whenever You need to select those permissions by columns or tables remember that some rules don't apply to security measures on Your server, like "We are all adults here" or "KISS - Keep It Simple Stupid". Personally, I prefer to create a minimal amount of users with only the necessary authorization to manipulate or collect data from DB.
Remember, that leak of data can have tremendous consequences, and rebuilding the trust of Your users is extremely hard to accomplish.