my %defs = (
 colC => { type => 'CHAR', len => '(90)' },
 colH => { type => 'TIMESTAMP' }
);
my $table_def = join ',', map { 
 if ($defs{$_}) {
  "$defs{$_}{type} column $_" . ($defs{$_}{len} || '')
 } else {
  "INT column $_"
 }
} @columns;