Question

Is there an easier way to do this instead of writing the same line of code 100+ times? I need the value of the field L_key each time as you will notice:

$query1 = "SELECT L_key FROM profiles WHERE v_key = '$L1_key'";
$result = mysqli_query($dbh, $query1);
if ($row = mysqli_fetch_array($result)) 
{
    $L2_key = $row['L_Key'];
    $query2 = "UPDATE profiles SET min = min + 1 WHERE v_key = '$L2_key'";
    mysqli_query($dbh, $query2);
} 

$query3 = "SELECT L_key FROM profiles WHERE v_key = '$L2_key'";
$result = mysqli_query($dbh, $query1);
if ($row = mysqli_fetch_array($result)) 
{
    $L3_key = $row['L_Key'];
    $query2 = "UPDATE profiles SET min = min + 1 WHERE v_key = '$L3_key'";
    mysqli_query($dbh, $query2);
} 

$query3 = "SELECT L_key FROM profiles WHERE v_key = '$L3_key'";
$result = mysqli_query($dbh, $query1);
if ($row = mysqli_fetch_array($result)) 
{
    $L4_key = $row['L_Key'];
    $query2 = "UPDATE profiles SET min = min + 1 WHERE v_key = '$L4_key'";
    mysqli_query($dbh, $query2);
} 

$query3 = "SELECT L_key FROM profiles WHERE v_key = '$L4_key'";
$result = mysqli_query($dbh, $query1);
if ($row = mysqli_fetch_array($result)) 
{
    $L5_key = $row['L_Key'];
    $query2 = "UPDATE profiles SET min = min + 1 WHERE v_key = '$L5_key'";
    mysqli_query($dbh, $query2);
} 

Do I use a loop? If so, can you please show me a code to execute this over and over as I am still learning and do not know what a loop is? Or, is there a different method?

Answer 1

You have a recursive structure in your profiles table (v_key => (l_key : v_key)=> ( l_key... )) and SQL does not really handle recusion terribly well with simple queries. Your options are to write a stored procedure or handle this with PHP. Since your a beginner, I’d imagine that PHP is far simpler for this task:

<?php
// define a variable on the outside -- we'll need it for each iteration
$lKey;
// If you know how many are going to be used, use a for loop because 
// then you know you won't get some sort of nasty infinite recursion issue.
// $count is however many times this needs to operate.
for($i = 0; $i < $count; $i++ )
// while( true ) // <-- this will keep going until "break" is called.
// If you don't know how many will be used. Comment out the for loop
// and uncomment thie while loop.
{
    // your initial query -- I added a limit because you only need one
    // and there is no sense in doing anything more than what you need
    $query1 = "SELECT L_key FROM profiles WHERE v_key = '$lKey' LIMIT 1";
    $result = mysqli_query($dbh, $query1);
    if ($row = mysqli_fetch_array($result)) // so far so good. 
    {
        $lKey = $row['L_Key']; // assign that outside variable to the new key
        // and run the necessary update.
        $query2 = "UPDATE profiles SET min = min + 1 WHERE v_key = '$lKey'";
        mysqli_query($dbh, $query2);
    } 
    else
    {
        break;
    }
    // as of right now, $lKey is now the value from the select above.
    // which means that you'll be able to start the next loop with it.
}