my @_STORAGE;

sub recursive_store {
   $query[$level] = "SELECT ...";
   my $sth = $dbh->prepare($query[$level]);
   $sth->execute;
   $_STORAGE[$level]= $sth->fetchall_arrayref;
   $sth->finish();
}

&recursive_store($level);

# Example access:
print _STORAGE[$level][$row][$col];

# Show what we have:
use Data::Dumper;
print Dumper \@_STORAGE;