[petteyg359]

In that case, assuming that every user has a unique ID... This is the code I use for inserting MMO characters of registered users into a database of mine. $nummac is set before this, after reading login information from the vB database. $charid is an array of all the unique character IDs. Would obviously have to be modified a bit to work in your script. You would then use 'UPDATE blahtable SET blahattribute = "blue" WHERE blahusername = "IAMBLAH"' to update userdata.

$charinsqa = 'INSERT INTO userskills (characterid) VALUES ';
for ($i = 0; $i < $nummac; $i++) {
 $existquerya = 'SELECT characterid FROM userskills WHERE characterid = "'.$charid[$i].'"';
 $existresulta = mysql_query($existquerya);
 $existrowa = mysql_num_rows($existresulta);
 mysql_free_result($existresulta);
 if (!$existrowa) {
  $charinsqab = $charinsqa.'("'.$charid[$i].'")';
  mysql_query($charinsqab) or die('Insert failed: '.mysql_error());
 }
}

unset($charinsqa);
unset($charinsqab);

My code:
Doesn't perform any INSERTs unless new users are found.
Old inactive users must be removed from the table manually.

Your code:
Performs many INSERTs every time.
Removes old inactive users by rewriting the entire table every time.

If you continue to use your code, that delete statement should still be changed to 'TRUNCATE TABLE tablename'. TRUNCATE is rather more efficient than DELETEing every row.