rivers/stack-years.pl

#!/usr/bin/perl -w

use strict;
# use diagnostics;
use DBI;
use POSIX;
use Data::Dumper;

my $station = shift @ARGV or die;

my $db = DBI->connect("dbi:SQLite:dbname=rivers.db") or die $DBI::errstr;

my $years_st = $db->prepare("select distinct substr(timestamp, 1, 4) from levels where stationid=?");
my $getdata_st = $db->prepare("select strftime('2000-%m-%dT%H:%M:%S.000Z', timestamp) as t, level from levels where stationid = ? and timestamp like ? || '-%'");

$years_st->execute($station);
my @years = @{$years_st->fetchall_arrayref};

my %data;
foreach my $y_ref (@years) {
    my $y = $y_ref->[0];
    $getdata_st->execute($station, $y);
    while(my $row = $getdata_st->fetchrow_arrayref) {
        $data{$row->[0]}{$y} = $row->[1];
    }
}
# print Dumper(\%data);

foreach my $ts (sort keys %data) {
    print "$ts\t";
    foreach my $y_ref (@years) {
        my $y = $y_ref->[0];
        print $data{$ts}{$y} || '-', "\t";
    }
    print "\n";
}