500 Error On Javascript, Ajax Update Of Mysql Cell

jquery.js?ver=1.12.4-wp:4 POST https://xyz/update.php 500 (Internal Server Error) send @ jquery.js?ver=1.12.4-wp:4 ajax @ jquery.js?ver=1.12.4-wp:4 myFunction @ 6011c7

Solution 1:

The issue should be with the URL, it must be absolute I think.

jQuery.ajax({
    //....
    url: 'http://yourwebsite.com/wp-content/themes/yummy/update-waitlist.php'// ...

The WordPress way

You must enqueue your JS file script.js before with same handle and then localize after it

Localize the script to pass generic data. We will pass the ajax_url with my_ajax object.

functions.php

wp_localize_script('your-script-handle', 'my_ajax', array('ajax_url' => admin_url('admin-ajax.php')));

Then in your script file, you can use the my_ajax object to get the AJAX URL. Define a action function_1 which will be executed when this AJAX call is requested.

script.js

jQuery.ajax({
    type: 'post',
    url: my_ajax.ajax_url,
    data: {
      action: 'function_1',
    }
    success: function(data){
        // callback function
    }
});

Define a function and attach it with Ajax action that will query the database & returns the result.

functions.php

add_action('wp_ajax_function_1', 'function_to_execute_some_query'); // logged in user can make a call
add_action('wp_ajax_nopriv_function_1', 'function_to_execute_some_query'); // non logged in user can make a callfunctionfunction_to_execute_some_query() {
    global$wpdb;
    $results = $wpdb->query( $wpdb->prepare("UPDATE 'wp_wpdatatable_4' SET `currentstatus` = 
    'myupdate1' WHERE wdt_ID = '1'"));
    die($results);

}