The following works fin for me - 
$dbh = DBI->connect("DBI:mysql:database=$serverDb;host=$serverName;por
+t=$serverPort",$serverUser,$serverPass);
$sth = $dbh->prepare("SELECT code,number FROM $serverTabl_4 WHERE name
+ = ? ORDER BY number DESC");
$sth->execute($surname);
my $ref;

while( $ref = $sth->fetchrow_hashref) 
{
  $codes{$ref->{code}} = $ref->{number};
  print $ref->{number},"\n"; 
}

[download]
but where I use the following - 
$dbh = DBI->connect("DBI:mysql:database=$serverDb;host=$serverName;por
+t=$serverPort",$serverUser,$serverPass);
$sth = $dbh->prepare("SELECT code,sum(number) FROM $serverTabl_4 group
+ by code");
$sth->execute();

while( $ref = $sth->fetchrow_hashref) 
{
 # $sum{$ref->{code}} = $ref->{number};
 print $ref->{number},"\n"; 
}

[download]

I get a warning saying that print uses an uninitianlized value,
What am I doing wrong? The statement (in mysql.exe) - SELECT code,sum(number) FROM surname_26 group by code; gives me - 
+------+-------------+
| code | sum(number) |
+------+-------------+
|    1 |        1087 |
|   21 |         606 |
|   22 |          77 |
|   23 |          26 |
|   24 |          84 |
|   25 |          43 |
|   26 |          14 |

[download]
etc,etc....
Thanks.

In reply to using fetchrow_hashref by Baz

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