Please help with mysql/php question

[Nullifi3d]

Yes, I only need the usernames, but I was going to store the userid's because there may be many ids stored for each post which (if stored usernames) may contain a string longer then 250.

Basically I am creating a praise the post hack for use on my forum. It works the opposite of report this post. A user can praise a post if they find it helpful. As of right now the hack sends the poster a pm notifying them that someone praised their post and then it updates ther poster's praises count (stored in the table user).

I need to also add the person's userid (who is praising the post) to the field (praisers) in the table post when a post is praised. This way I can list all users who have praised this post on the postbit. As well I can restrict users from praising a post twice.