Sankalp,
Retrieving data from database has been handled in service.php which is loaded in index.php using AJAX request. You can combine both into a single php file according to your requirement / coding-style. Please take a look at this updated sample project.
The sample projects shared seems to be working fine, can you kindly check browser console for any errors? Also can you kindly brief more about the issue you are facing like screenshot of the output, whether the chart is rendering with just axis atleast or chart is not at all rendering, etc which helps us understand your scenario better and help you out?
Please refer PHP Chart from Database for an example on rendering chart in PHP from database. Also you can download & checkout PHP Samples from our download page.
—
Vishwas R
Team CanvasJS