You need nested loops. The outer loop selects the data that you want to keep. The inner loop updates the CODE if a matching ID is found. 
use strict;
use warnings;
use Data::Dumper;

my $test_data = [
    {'ID' => '1212', 'Name' => 'JOE'  , 'Number' => 'XY1', 'CODE' =>  
+'6',},   
    {'ID' => '1212', 'Name' => ''     , 'Number' => 'XY1', 'CODE' => '
+10',},
    {'ID' => '4456', 'Name' => 'MARIA', 'Number' => 'TYX', 'CODE' =>  
+'6',},
    {'ID' => '4456', 'Name' => ''     , 'Number' => 'TYX', 'CODE' => '
+10',},
    {'ID' => '8765', 'Name' => 'JEAN' , 'Number' => 'HPO', 'CODE' =>  
+'6',},
];

my @result;
foreach my $data ( @{ $test_data } ) {
    next if !$data->{Name};
    my $id = $data->{ID};
    push @result, $data;
    foreach my $temp ( @{ $test_data } ) {
        if (!$temp->{Name} and ($temp->{ID} eq $id)) {
            $result[-1]->{CODE} = $temp->{CODE};
            last;
        }
    }
}

print Dumper(\@result);

[download]

OUTPUT

$VAR1 = [
          {
            'ID' => '1212',
            'CODE' => '10',
            'Number' => 'XY
            'Name' => 'JOE'
          },
          {
            'ID' => '4456',
            'Name' => 'MARI
            'Number' => 'TY
            'CODE' => '10'
          },
          {
            'CODE' => '6',
            'Number' => 'HP
            'Name' => 'JEAN
            'ID' => '8765'
          }
        ];

[download]
Bill

In reply to Re: Add value from one array element into another of same ID by BillKSmith
in thread Add value from one array element into another of same ID by Anonymous Monk

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