PHP chart diagram to display skipped entry - php

Question

I'm trying to create a graph like this http://jsfiddle.net/9mmrbjt7/1/
I have a script created that will add the data to the graph. The date and the value is stored in db and it works just fine.
The php script counts the number of dates and uses it as a value and assign it to the date.
The problem is if someone miss one day it skips the value which I understand.
So how can I assign value zero to skipped day?
2014-07-23
2014-07-23 = 2,
2014-07-24 -> wasn't submitted so the 0 should be added to the graph with the date.
2014-07-25
2014-07-25
2014-07-25= 3,
php script
$user_curr_id = $_SESSION['user_id'];
$sql = mysqli_query($con,"SELECT * FROM rosary WHERE user_ids = $user_curr_id ORDER BY datum ASC");
$array1 = array();
while($row = mysqli_fetch_array($sql)){
$array1[] = '"' . $row['datum'] . '"';
}
$tags = implode(', ', array_unique(array_map('trim',explode(',',implode(',',$array1)))));
$sql = mysqli_query($con,"SELECT datum, COUNT(datum) cnt
FROM rosary
WHERE user_ids = $user_curr_id
GROUP BY datum;");
$result = array();
while ($row = mysqli_fetch_array($sql)) {
$result[] = $row['cnt']; // add the content of field cnt
}
in js script
labels : ["Start",<?php echo $tags; ?>] -> list the dates from db
data : [0,<?php echo implode(',', $result); ?>]-> list values from db

Answer 1

php:
$sql = mysqli_query($con,"SELECT datum, COUNT(datum) as cnt
FROM rosary
GROUP BY datum
ORDER BY datum ASC;");
$result = array();
$start = null;
$end = null;
while ($row = mysqli_fetch_array($sql)) {
$result['"'.$row['datum'].'"'] = $row['cnt'];
if(is_null($start)) $start = $row['datum'];
$end = $row['datum'];
}
$res_array = array();
if(!is_null($start)){
$i = strtotime($start);
while($i <= strtotime($end)){
$res_array['"'.date('Y-m-d',$i).'"'] = 0;
$i = strtotime("+1 day",$i);
}
}
foreach($result as $date => $val){
$res_array[$date] = $val;
}
in js script
labels : ["Start",<?php echo implode(',',array_keys($res_array)) ?>],
data : [0,<?php echo implode(',', array_values($res_array)); ?>],