Actually, there's no real need to sort the keys. And there's definitely no need to sort them more than once: just create an array with them. A hash slice makes the map unnecessary. Here's a modified version of your code:

#### or with placeholders:
my $col_spec = join ',', keys %data;
my $val_spec = join ',', ('?') x keys %data;
my $sql      = "insert into my_table ($col_spec) values ($val_spec)";

$dbh->prepare($sql)->execute(@data{keys %data});
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In case you want to use the perepared statement more than once, there's no ganratee that keys() will return the keys in the same order over different hashes even though they have the same keys:

#### or with placeholders:
my(@col_names, $sth);
{
    local $" = ',';
    @col_names   = keys %data;
    my $val_spec = join ',', ('?') x @col_names;
    my $sql      = "insert into my_table (@col_names) values ($val_spe
+c)";
    $sth = $dbh->prepare($sql);
}
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And much later (just make sure $sth and @col_names are still in scope):

$sth->execute(@data{@col_names});
[download]