use Modern::Perl '2014';
use DBI;

my $dbfile = 'c:/data/school.sqlite';
my $dbh =
  DBI->connect( "dbi:SQLite:dbname=$dbfile", "", "", { RaiseError => 1 } );

my $sth = $dbh->prepare('INSERT INTO students (id, name) VALUES (?, ?)');
while (<DATA>) {
    chomp;
    last if /grades.txt/;
    next unless $_;
    next if /^\*\*\*/;
    say $_;
    my ( $id, $name ) = split /:/;
    $sth->execute( $id, $name );
}

$sth =
  $dbh->prepare('INSERT INTO results (id, course, score) VALUES (?, ?, ?)');
while (<DATA>) {
    chomp;
    next unless $_;
    next if /^\*\*\*/;
    my ( $id, $course, $score ) = split /\s+/;
    $sth->execute( $id, $course, $score );
}

my $ary_ref = $dbh->selectall_arrayref(
'SELECT name, sum(score), avg(score), min(score), max(score) FROM results JOIN students WHERE students.id = results.id GROUP BY results.id ORDER BY name'
);

printf "%20s %10s %8s %8s %8s\n", qw/Name Total Average Min Max/;
for my $line (@$ary_ref) {
    printf "%20s %10d %8d %8d %8d\n", @$line;
}

$ary_ref = $dbh->selectall_arrayref(
    'SELECT course, avg(score) FROM results GROUP BY course ORDER BY course');

printf "\n%10s %8s\n", qw/Course Average/;
for my $line (@$ary_ref) {
    printf "%10d %8d\n", @$line;
}

__DATA__

***students.txt***
122334:James,Lebron:
222223:Duncan,Tim:
244668:Bryant,Kobe:
355779:Durant,Kevin:
******************

***grades.txt***
122334 1 98
222223 1 86
...(snip)...
244668 5 95
355779 5 94
****************

##</code><code>##

                Name      Total  Average      Min      Max
         Bryant,Kobe        466       93       89       95
          Duncan,Tim        462       92       86       96
        Durant,Kevin        468       93       90       96
        James,Lebron        485       97       96       98

    Course  Average
         1       90
         2       93
         3       95
         4       95
         5       95