Question

I am trying to create a simple PHP MySQL driven message client.

So far I have two tables:

users which holds information about each person registered on the site. userID, firstName, lastName etc.

mail which contains a MessageID, fromUserID, toUserID, messageSubject, messageBody , dateSent etc.

Users can register and then log in. Once they are logged in they can view their ‘inbox’.

What I am trying to figure out is how to list all the messages, and a preview for each message saying who it is from. Obviously I can get the fromUserID field from the mail table but that doesn’t mean anything to the user, it is just a number, I want to use the userID and query the users table and pull from that the sender’s first and last name.

I know I can use JOIN but I am not sure how to go about it, or can I use a sub query? What is better?

Any suggestions are very welcome.

Answer 1

You’re going to want to join the users table, something like:

SELECT m.*, u.*
FROM mail m
  LEFT JOIN users u ON u.id = m.fromUserID
WHERE m.toUserID == 'LoggedInUserId'