my @db = (1, 3, 5, 7, 9, 11);
my @in = (1, 2, 5, 8, 9, 10, 13);
# results in: my @db = (3,  7, 11);

##</code><code>##

my @db = (1, 3, 5, 7, 9, 11);
my @in = (21, 22, 25, 28, 29, 210, 213);
# results in: my @db = (1, 3, 5, 7, 9, 11, 21, 22, 25, 28, 29, 210, 213);