Question

I have 2 tables

members
=======
id
f_name  // get these values.
l_name
email

friends
=======
to
from

The users’s I’d is the value $member_id, if it is present in “to” or “from” I want it to not return the other value of that row, so only non-friends are shown.

Im creating a page to allow members to search through the database to add their friends by email, or name.

I’d like to return all rows from members where there is no record of the userid in either the “to” or “from” columns of the friends table.

I know how to do most basic mysql but joins are an issue for me, i don’t really understand how to write them, if anyone can help me out and maybe even explain it a bit that would be great!

My query now:
  $query = "SELECT * FROM members WHERE f_name LIKE '%" . $word . "%' OR l_name LIKE '%" . $word . "%' OR mc_name LIKE '%" . $word . "%' OR email LIKE '%" . $word . "%' LIMIT 10";
//Where $word is the search term.

Modified Query

SELECT * FROM members WHERE id NOT IN (SELECT to FROM friends WHERE frm=$member_id) AND $member_id NOT IN (SELECT frm FROM friends WHERE to=$member_id) AND f_name LIKE '%" . $word . "%' OR l_name LIKE '%" . $word . "%' OR mc_name LIKE '%" . $word . "%' OR email LIKE '%" . $word . "%' LIMIT 10

Answer 1

Edited

So, suppose a user with id 3:

SELECT * 
FROM members
WHERE id <> 3 
AND id NOT IN (SELECT to FROM friends WHERE from = 3)
AND id NOT IN (SELECT from FROM friends WHERE to = 3)
[Other conditions....];

OR

SELECT * 
FROM members
LEFT JOIN friends
ON (members.id = friends.to
    OR members.id = friends.from)
AND (members.to = 3 
     OR members.from = 3)
WHERE friends.to IS NULL
AND id <> 3
[Other conditions....];

Maybe consider change the name of your “from” and “to” columns, to avoid confusion, because FROM and TO are reserved words.

Also, you can use the reserved word EXPLAIN , before the query, to see the difference of the number of rows being fetched.