I'd prefer to set @question_marks like this:

my @question_marks = ('?') x @columns;
[download]

which populates the whole thing at once and eliminates an auxiliary variable.

You should localize $", moving it inside braces close to where it's needed.

        else {
            local $" = ', ';
            $sth = $dbh->prepare(
                       "INSERT INTO $table (@columns) VALUES (@questio
+n_marks)"
                   );
            $sth->execute(@csv_values);
        }
[download]

That will prevent surprises in case arrays are stringified elsewhere.

After Compline,
Zaxo