Dear monks, I would like to implement a group by feature in my program, this without having to export my array content in a file and process it in a database in order run a group by! I am not familiar with hashes yet as it looks like that it is the way to go. DBI could help also. Looking for a simple solution. This is a sample content of my array: 
Account    Entity    Unit    Jan    Feb    Mar
Account01    Entity01    Unit01    1    2    3
Account01    Entity01    Unit01    4    5    6
Account01    Entity01    Unit01    7    8    9
Account02    Entity02    Unit02    10    11    12

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And the expected result: 
Account    Entity    Unit    Jan    Feb    Mar
Account01    Entity01    Unit01    12    15    18
Account02    Entity02    Unit02    10    11    12

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This is what I run from my database: 
CREATE TABLE concat_FRA3 AS
  SELECT Account, Entity, Unit, 
    SUM(Jan) Jan,
    SUM(Feb) Feb,
    SUM(Mar) Mar
  FROM concat_FRA2
  GROUP BY Account, Entity, Unit;

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If found this piece of code but not clear on how to define the hash header/keys (Account to Mar) and columns to group (Jan to Mar) 
# Store
my %storage;
foreach my $row (@$result_set) {
    my $hash_key = encode_hash_key(row);
    my $new_row = $row;
    if (exists $storage{$hash_key}) {
        $new_row = merge_rows($row, $storage{$hash_key});
    }
    $storage{$hash_key} = $new_row;
}

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Thank you for any hint or advice. Sebastien

In reply to Group by from array by sroux

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