Question

I have a group feature on my website that allows 1 user to put the userids of any of his or her friends into an invitedusers column. I need to do an SQL search to determine whether the logged-in user’s ID has been stored in any invitedusers columns by his or her friends.
How can I do this with an sql search?

EX: My column is invitedusers, and inside that column is stored the following, (234,394,479)
When Userid 234 has logged in, I need to search to see whether any columns have userid 234 stored inside the invitedusers column.

SELECT userid, name... FROM mytable WHERE invitedusers = ?

*I looked at the SQL IN operator along with FIND_IN_SET but no help with either.*

Answer 1

Assuming that you’re really using 234,394,479 as value of one column (you at least should use ,234,394,479, to be able to do WHERE invited LIKE '%,234,%' in your query) you should rebuild your user tables, remove field invited_users and create table like this:

CREATE TABLE invited_users (
  id INT AUTO_INCREMENT,
  owner_id INT, -- Who's input it is
  target_id INT, -- What's the target user
  PRIMARY KEY ( id),
  UNIQUE ( owner_id, target_id),
  -- Indexes (FOREIGN KEYs!) to users table
);

And than just select list of users who invited user 234 with query:

SELECT users.id, users.name
FROM invited_users
INNER JOIN users ON invited_users.owner_id = users.id
GROUP BY users.id
WHERE invited_users.target_id = 234