$sth->bind_columns(\$var1, \$var2, \$var3);

##</code><code>##

@list_of_refs_to_vars_to_bind = (\$var1, \$var2, \$var3);
$sth->bind_columns(@list_of_refs_to_vars_to_bind);

##</code><code>##

map { $$_ = "null" if (!defined $$_); } @list_of_refs_to_vars_to_bind;