Bars are showing up even when value is zero - Google Charts - mysql

Question

I have created a monthly chart using Google charts but the bars are showing up even when the value is zero.
Here is the screenshot of it
and here is the code and I know code is vulnerable to SQL Injection. You can ignore it. This is only for testing purpose
Previously order_total_amount column was set to "VARCHAR" datatype, then someone suggested that it should set to the "INT". So I changed it from Varchar to Int. But that didn't solved the problem. Bar is still showing up despite having 0 value
<script type="text/javascript">
google.charts.load('current', {'packages':['bar']});
google.charts.setOnLoadCallback(drawChart);
function drawChart() {
var data = google.visualization.arrayToDataTable([
['Monthly', 'Sales'],
<?php
$sale_chart = "SELECT
SUM(IF(month = 'Jan', total, 0)) AS 'Jan',
SUM(IF(month = 'Feb', total, 0)) AS 'Feb',
SUM(IF(month = 'Mar', total, 0)) AS 'Mar',
SUM(IF(month = 'Apr', total, 0)) AS 'Apr',
SUM(IF(month = 'May', total, 0)) AS 'May',
SUM(IF(month = 'Jun', total, 0)) AS 'Jun',
SUM(IF(month = 'Jul', total, 0)) AS 'Jul',
SUM(IF(month = 'Aug', total, 0)) AS 'Aug',
SUM(IF(month = 'Sep', total, 0)) AS 'Sep',
SUM(IF(month = 'Oct', total, 0)) AS 'Oct',
SUM(IF(month = 'Nov', total, 0)) AS 'Nov',
SUM(IF(month = 'Dec', total, 0)) AS 'Dec'
FROM
(SELECT
MIN(DATE_FORMAT(order_date, '%b')) AS month,
SUM(order_total_amount) AS total
FROM
invoice_order
WHERE
user_id = '$user_id'
GROUP BY YEAR(order_date) , MONTH(order_date)
ORDER BY YEAR(order_date) , MONTH(order_date)) AS sale";
$sale_chart_query = mysqli_query($connection,$sale_chart) or die(mysqli_error($connection));
$sale_chart_array = mysqli_fetch_assoc($sale_chart_query);
foreach($sale_chart_array as $x => $val) { ?>
['<?php echo $x; ?>','<?php echo $val; ?>'],
<?php } ?>
]);
var options = {
};
var chart = new google.charts.Bar(document.getElementById('chart_div'));
chart.draw(data, google.charts.Bar.convertOptions(options));
}
</script>
After replacing zero with null, that is how it showing up the result

Answer 1

using a value of null in the chart's data table will prevent a bar from appearing.
see following working snippet...
in this case, you're including strings instead of numbers in the data table.
remove the single quotes from the second array value, here...
['<?php echo $x; ?>',<?php echo $val; ?>],
google.charts.load('current', {
packages: ['bar']
}).then(function drawChart() {
var data = google.visualization.arrayToDataTable([
['Monthly', 'Sales'],
['Jan', 1000],
['Feb', null],
['Mar', null],
['Apr', null],
['May', 40000],
['Jun', null],
['Jul', null],
['Aug', null],
['Sep', null],
['Oct', null],
['Nov', null],
['Dec', null]
]);
var options = {};
var chart = new google.charts.Bar(document.getElementById('chart_div'));
chart.draw(data, google.charts.Bar.convertOptions(options));
});
<script src="https://www.gstatic.com/charts/loader.js"></script>
<div id="chart_div"></div>