I have found myself using this trick (I resolved, for one client, to give them code which caused no warnings whatsoever under normal usage):

# When retrieving data from DBI
my $Ref = {map(defined $_ ? $_ : '', %{$sth->fetchrow_hashref})};
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This feels a bit odd, but is easier than only checking the values of the hash. Of course, you can do the same with arrays...

my $Ref = [map(defined $_ ? $_ : '', @{$sth->fetchrow_arrayref)];
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Since I am also lazy, I found this much better than always writing:

print "<td> @{[ defined $Var ? $Var : '' ]} </td>";
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Oh, well. Just sharing some more of my strange code... :-)

Russ