The learning curve is less than you probably think. Assuming postgres, here is the highest price for hour 6 in the last 5 days. 
use DBI;
my $dbh = DBI->connect(
  "dbi:Pg:host=$host;database=$database",
  $user,
  $password,
  {
    AutoCommit => 0,
    RaiseError => 1,
  },
) or die "Can't connect: $DBI::errstr";

my $data = $dbh->selectall_arrayref(qq{
  SELECT MAX(price) as max_price
  FROM data_log
  WHERE price_date > now()::date - 5
    AND to_char(price_date, 'HH24') = '06'
}) or die "Cannot prepare: $DBI::errstr";

print $data->[0][0];

[download]
As you see, the DBI API is not that complex. Basic selects are not that hard. Inserts aren't that bad either. The real trickiness will be figuring out the date-time handling in your database, but you can just look at an appropriate manual until you get familiar with them. Oh right, and you have to create the table and indexes. But you only have to figure that out once.

In reply to Re^5: Invert a hash... not a FAQ (I hope) by tilly
in thread Invert a hash... not a FAQ (I hope) by djacobow

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