"Timestamp","Average","Unit"
"2017-03-01T04:05:00Z","145.8","Count"
"2017-03-01T10:35:00Z","182.2","Count"
"2017-03-01T05:30:00Z","180.2","Count"

##</code><code>##

use warnings;
use strict;
use Text::CSV;
use JSON::MaybeXS;

my $json = <<'END_JSON';
{
    "Datapoints": [
        {
            "Timestamp": "2017-03-01T04:05:00Z",
            "Average": 145.80000000000001,
            "Unit": "Count"
        },
        {
            "Timestamp": "2017-03-01T10:35:00Z",
            "Average": 182.19999999999999,
            "Unit": "Count"
        },
        {
            "Timestamp": "2017-03-01T05:30:00Z",
            "Average": 180.19999999999999,
            "Unit": "Count"
        }
    ],
    "Label": "DatabaseConnections"
}
END_JSON

my $data = decode_json($json);

my $csv = Text::CSV->new({auto_diag=>2,
	binary=>1, eol=>"\n", always_quote=>1 });

my @fields = qw/ Timestamp Average Unit /;
$csv->print(select, \@fields);
for my $datapoint ( @{ $data->{Datapoints} } ) {
	$csv->print(select, [ map {$datapoint->{$_}} @fields ]);
}