Switch Case - not all cases work - php

Question

At the moment I am writing a calendar. According to the chosen motn ($monthnum), I store the abbreviated month name ($monthabbr) in a database. For that I use a switch-case construct. It works for all months, except for 08-August and 09-September. Since I used the same code for all months, I don't know why it's not working. I am close to the edge to start all over again, but before that I'll better ask if you see an error.
switch( $monthnum ) {
case 01:
$monthabbr = 'Jan';
break;
case 02:
$monthabbr = 'Feb';
break;
case 03:
$monthabbr = 'Mär';
break;
case 04:
$monthabbr = 'Apr';
break;
case 05:
$monthabbr = 'Mai';
break;
case 06:
$monthabbr = 'Jun';
break;
case 07:
$monthabbr = 'Jul';
break;
case 08:
$monthabbr = 'Aug';
break;
case 09:
$monthabbr = 'Sep';
break;
case 10:
$monthabbr = 'Okt';
break;
case 11:
$monthabbr = 'Nov';
break;
case 12:
$monthabbr = 'Dez';
break;
}

Answer 1

Change 01, 02, ..., 09 to just 1, 2, ..., 9 (drop the zeros).
By starting an integer literal with a 0 indicates that it should be interpreted as an octal number (a number in base 8).
For octal numbers the digits 8 and 9 are illegal.
Further reading:
PHP Manual: Integers
(Btw, you may want to consider using an array or a map from integer to string, and just look up the string using something like monthAbbrs[$monthnum])

Answer 2

You can avoid this issue by using quotes
switch($date){
case "01": $month = "January"; break;
case "02": $month = "February"; break;
case "03": $month = "March"; break;
case "04": $month = "April"; break;
case "05": $month = "May"; break;
case "06": $month = "June"; break;
case "07": $month = "July"; break;
case "08": $month = "August"; break;
case "09": $month = "September"; break;
case "10": $month = "October"; break;
case "11": $month = "November"; break;
case "12": $month = "December"; break;
}

Answer 3

I dont know what the purpose is but a better way is to parse your date
$mysqldate = date( 'Y-m-d H:i:s', $phpdate );
$phpdate = strtotime( $mysqldate );
see here
and then format it in the way you like:
// Prints something like: Monday 8th of August 2005 03:12:46 PM
echo date('l jS \of F Y h:i:s A');
see here