loop problem within a statement - php

Question

i hope someone can help about to scream!
basically I am trying to do a few things with the statement below;
First i want to check if the user id exists in member_categories_position.
If it Does i want then to exclude all entries from the second statement where member_id equals all results from the first statement
the third statement is the else statement that displays if the member_id is not present in the member_categories position.
PROBLEM - the result from the first system loops fine, however when i try and insert into the second statement (!='$memid') is produces no results and has no effect. I think the problem is that $memid is a looped result.
How do i get the second statement to say that any member_id that is in member_categories_position will not show in that statement?
$sql2 = "
SELECT *
FROM member_categories_position a
JOIN member_users b
ON b.id = a.member_id";
$rs2 = mysql_query($sql2);
while ($row = mysql_fetch_array($rs2))
{
$memid = "".$row['member_id']."";
}
if(mysql_num_rows($rs2) != 0)
{
$new= "
SELECT *
FROM member_categories
JOIN member_users
ON member_categories.member_id=member_users.id
JOIN member_config
ON member_categories.member_id=member_config.member_id
WHERE
member_categories.categories='$category'
AND member_categories.member_id !='$field'
GROUP BY member_config.member_id
ORDER BY RAND() limit 0,42";
$rs = mysql_query($new);
while ($row = mysql_fetch_assoc($rs))
{
echo "result excluding member ids from the first statement";
}
echo "<div class=\"clear\"></div>";
}
else
{
$new= "
SELECT *
FROM member_categories
JOIN member_users
ON member_categories.member_id=member_users.id
JOIN member_config
ON member_categories.member_id=member_config.member_id
WHERE
member_categories.categories='$category'
GROUP BY member_config.member_id
ORDER BY RAND() limit 0,42";
$rs = mysql_query($new);
while ($row = mysql_fetch_assoc($rs))
{
echo "Result with all member ids";
}
echo "<div class=\"clear\"></div>";
} } <-- (second is a stray from original post)

Answer 1

$memid is not in scope since it appears to be defined inside the loop. Try defining $memid = ''; at the top of your script.. like this.
$memid = '';
$sql2 = "
SELECT *
That way it will be defined when you use it below..