Question

I have a user with his unique username in a mysql table, but I have to test and do many queries to find it. I wonder if its a better way to avoid all does queries to the db.

I have multiple rows in the table with columns like user1, user2, user3, user4 up to 30.

for ($x=0; $x < 30; $x ++){

    $user = "user"; 
    $user .= $x; //generate user1, user2, user3 etc


    $result=mysql_fetch_object(mysql_query("SELECT * FROM table WHERE ".$user."='".$_SESSION['username']."'"));
    if ($result){

Now if the $_SESSION['username'] is user30 in the table I do 29 queries before $result is true and I can work with the results. Is there a better way to do this? How important is this anyway. Is there a big difference in cpu demand for 1 query and 30 queries?

Answer 1

While you should really have just one user column, you could use a loop to build one big query rather than doing 30 small ones.

<?php
$query = "SELECT * FROM table WHERE ";
foreach(range(1,30) as $num) {
    $query .= " user$num = '{$_SESSION['username']}'";
    if($num < 30) $query .= " OR ";
}
print $query;
$result=mysql_fetch_object(mysql_query($query));
?>