A hash cannot have multiple values for the same key. You will need to rethink your data structure.

Consider storing array references as values instead of hash references as values:

 { 
'1'=> [{
      'clz=>'nit'
      'degree'=>'ph.d',
      'name'=>'teja'
      },
      {
      'clz=>'iit'
      'degree'=>'M.tech',
      'name'=>'teja'
      }],####This block not coming in output
'2'=>[{
       'clz=>'mit'
      'degree'=>'ravi',
      'name'=>'B.Tech'
}]
};
[download]

This change will also need changes in your code on how you fill the data structure and how you output your data structure.

I am new to perl. Could you please guide me how to achieve that.Thanks in advance.

See perlintro and perldsc maybe.

The idea is to initialize $data{ $master_key } with an empty array for each id and then to push every found element onto that array:

...
$data{$master_key} ||= []; # if we haven't seen $master_key yet, creat
+e a fresh array
my %this_set;
for my $col(1 .. $eSheet->{MaxCol})
{
# Some logging for debugging
if( !defined $eSheet->{Cells}[$row][$col]) {
    print "Row $row: skipping empty column $col\n";
    next;
};
my $key= $eSheet->{Cells}[0][$col]->Value;
my $value = $eSheet->{Cells}[$row][$col]->Value;
$this_set{$key}=$value;
}
}
# Store our found set for that ID:
push @{ $data{ $master_key }}, \%this_set;
[download]

Where the spreadsheet is missing a master-key are you assuming the previous value ?

ID  NAME   Degree  Collage
 1   Teja   B.Tech   NIT
            M.Tech   IIT(the problem is in converting this line)
 2   Ravi   B.tech   MIT
[download]

poj