As Laurent_R said, your requirements have another dimension (or two), so my script won't work for this except for some of the basic ideas. You're probably going to want three hashes, one to collect per-hour values (%h) and one to collect per-minute value (%m), and one to collect database names (%db). Then you'll need to:

for each line
  parse out the date-hour, date-hour-minute, database name, and speed
  add speed to $h{date-hour}{database name}
  add speed to $m{date-hour-minute}{database name}
  $db{database name} = 1 # put database name in hash

loop through sorted keys of %db
  print them as headers, formatted to fit what's coming below
loop through keys of %h (sorted if you want)
  print the key (the date-hour)
  loop through sorted keys of %db
    print $h{$key}{database name}
  print a newline

now do the same with the per-minute hash %m
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Try coding that, and let us know if you need help.

Thanks a lot Aaron Sir !!!! I tried coding the way you said but not sure where I am going wrong, getting lot of errors "Use of uninitialized value in string". I tried debugging but in vain. Also no idea how to print the keys in a single line, I am not able to meet this requirement "print them as headers, formatted to fit what's coming below" Please do not mind for these silly mistakes, I am still beginner in perl.

#!/usr/bin/env perl
use strict; use warnings;

my %h;
my %m;
my %db;

while(<DATA>){
  chomp;
  my @fields = split;
  my ($date,$database_name,$speed) = @fields[1,2,3];
  my ($date_hour,$minute) = split /:/, $date ;
  my $date_hour_minute = join (':',$date_hour,$minute) ;
  
  $h{$date_hour}{$database_name} += $speed;
  $m{$date_hour_minute}{$database_name} += $speed;
  $db{$database_name} = 1;
}

for my $db_keys (sort keys %db){
    print "$db_keys";
    for my $h_keys (sort keys %h){
        print $h_keys;
            for my $db_keys (sort keys %db){
                print "$h{$h_keys}{$db_keys}";
                print "\n";
            }
    }
}
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Will be thankful to you if you could help me please...

You're getting close! The main problem is with your loop logic. You want to print a header line starting with "connectionTime," followed by the database names. You can do that with something like this:

print "    collectionTime";
for my $db_keys (sort keys %db){
    print "    $db_keys";          # adjust spaces to line things up
}
print "\n";
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Now you want to start going through the actual data, printing it so that it lines up with the headers. So this loop follows the previous one, instead of being inside it:

for my $h_keys (sort keys %h){
    print $h_keys;                         # print the date/hour
    for my $db_keys (sort keys %db){
        print "    $h{$h_keys}{$db_keys}"; # pad with enough spaces to
+ match header
   }
   print "\n";  # this goes outside the inner loop, to end the line
}
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I haven't tested that, but it's just a bit of an adjustment to what you had. Once it works, the next thing you'll probably want to look at is replacing the print statements with printf, which will help you line things up in columns even though the values are of different lengths.

One more thought: for efficiency's sake, we should probably sort the %db hash keys once and put them in an array, rather than re-sorting them every time we print a line. But it'll work this way, so we can deal with that next time.

Aaron B.
Available for small or large Perl jobs and *nix system administration; see my home node.

your data structure is obviously too simplified for the level of details that you want to display, your %h hash needs an extra level of information (the time). Once you have added that, it should be only a matter of displaying correctly.