use warnings;
use strict;

my $sql = <<SQL;
select A, B, C,
  (select D, E, F,
    (select G, H from AA where ID = Z) from BB where ID2 = X),
      I, J
        from CC;
SQL

my @parts = split /(\W+)/, $sql;
my @formatting = (undef);

for my $part (@parts) {
    print $part;

    if (lc $part eq 'select') {
        $formatting[-1] = 1;
        next;
    }

    if (lc $part eq 'from') {
        $formatting[-1] = undef;
        next;
    }

    if ($part =~ m'\)') {
        pop @formatting;
    }

    next if ! $formatting[-1];

    if ($part =~ m'\(') {
        push @formatting, undef;
        next;
    }

    print qq{ format \\"\%s|\\"} if $part =~ /\w/;
}