Auto?

[Cooper94]

$result=mysql_query("SELECT * FROM pilots ORDER BY date");
$num=mysql_rows_num($result);
$row = mysql_fetch_assoc($result);

$a = {$row['username']};
$a++;
$a;

How can I make $a equal the last username registered. So say the last one was RPA101 so the next would be RPA102.

[Maq]

Try this, I added some error checking and altered your SQL:

 

$sql="SELECT * FROM pilots ORDER BY date DESC LIMIT 1";
$result = mysql_query($sql) or die(mysql_error());
$row = mysql_fetch_assoc($result);
$a = $row['username'];
echo "Last User: " . $a;

[shadiadiph]

you could make it your primary key for example if  your primary key is pilotid when you call it fro your database or want to use it preceed it with RPA<?=$pilotid?>

[Maq]

I think I may have only answered part of your question.  You would have to strip off the integer value from RPA and one it.  You can ++ a string but when it reaches the max digit it will add a letter to your RPA.

[PFMaBiSmAd]

To prevent problems with concurrent registrations (on modern multi-tasking, interrupt/event/service driven operating systems, you cannot guarantee the order in which queries are executed), you must do one of the following to insure that you don't repeat a value -

 

Use an auto increment field for the number (prepend your letter code when it is retrieved) and let the database manage the generation of the next number.

 

Make the column a unique key and check for an error if you try to insert a duplicate value. Loop, incrementing and attempting to insert until you successfully insert a value.

 

Lock the table before the SELECT query and unlock it after an INSERT query so that you know the value you are generating and using is unique.

[shadiadiph]

PFMaBiSmAd a bit like what i suggested?