use strict;
my @to_insert = (
        { 'A' => 1, 'B' => 1 },
        { 'B' => 2 },
        { 'A' => 3 },
);

for my $row (@to_insert) {
        my $insertStmt;
        my $cols;
        my $vals;
        for my $col (keys %{$row} ) {
                $cols .= $col . ",";
                $vals .=  "?,";
        }
        $insertStmt = "insert into blah ($cols) values ($vals);";
        print "$insertStmt\n";

}