Hi Arturo

Thank you for reaching out to us.

Please check the Editing tab above the table - "ID column for editing". That has to be a unique, auto-increment integer column that will store the edited rows into the database. 

In the database table, you need to add a row ID column (a unique auto-increment column). You can do it using this query:

ALTER TABLE `youTableName`ADD COLUMN `id_column` INT AUTO_INCREMENT UNIQUE FIRST;

Then, in the Editing tab above the table, set this column to be the "ID column for editing", and it should work fine after that.

Hello Arturo

Sorry for the late response.

Please provide me a temporary WP-admin (administrator) user for your site where this happens, so we could log in and take a look ‘from the inside’ as that’s the most efficient way to see and resolve the issue. 

We do not interfere with any data or anything else except for the plugin (in case that’s a production version of the site), and of course, we do not provide login data to third parties. 

You can write credentials here just check PRIVATE Reply so nobody can see them except us.

Make sure to tell us on which front-end page this table is located, and the database access for the database from where this table is being pulled.

Thank you Arturo.

We found the issue. The detailed error is this:

Fatal error: Uncaught TypeError: mysqli_num_rows(): Argument #1 ($result) must be of type mysqli_result, bool given in /home/u112784341/domains/sdsconsultores.com/public_html/wp-content/plugins/wpdatatables/source/class.sql.php:271 Stack trace: #0 /home/u112784341/domains/sdsconsultores.com/public_html/wp-content/plugins/wpdatatables/source/class.sql.php(271): mysqli_num_rows() #1 /home/u112784341/domains/sdsconsultores.com/public_html/wp-content/plugins/wpdatatables/source/class.sql.php(99): PDTSql->prepare() #2 /home/u112784341/domains/sdsconsultores.com/public_html/wp-content/plugins/wpdatatables/controllers/wdt_ajax_actions.php(475): PDTSql->doQuery() #3 /home/u112784341/domains/sdsconsultores.com/public_html/wp-includes/class-wp-hook.php(303): wdtSaveTableFrontend() #4 /home/u112784341/domains/sdsconsultores.com/public_html/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters() #5 /home/u112784341/domains/sdsconsultores.com/public_html/wp-includes/plugin.php(470): WP_Hook->do_action() #6 /home/u112784341/domains/sdsconsultores.com/public_html/wp-admin/admin-ajax.php(187): do_action() #7 {main} thrown in /home/u112784341/domains/sdsconsultores.com/public_html/wp-content/plugins/wpdatatables/source/class.sql.php on line 271

It's coming from PHP version 8.0.7. and we will fix the issue in our next update.

Until then, I modified the file ../wp-content/plugins/wpdatatables/source/class.sql.php and modified this:

if (@mysqli_num_rows($result)) {
    $row = mysqli_fetch_assoc($result);
    if (isset($row['error'])) {
        $this->error = $row['error'];
        return false;
    } else {
        mysqli_data_seek($result, 0);
        return $result;
    }
} else {
    return false;
}

With this:

if(is_a($result, 'mysqli_result')){
    if (mysqli_num_rows($result)) {
        $row = mysqli_fetch_assoc($result);
        if (isset($row['error'])) {
            $this->error = $row['error'];
            return false;
        } else {
            mysqli_data_seek($result, 0);
            return $result;
        }
    } else {
        return false;
    }
} else {
    return false;
}

Now you can modify and add new rows without this error appearing.

One advice, though, since you're pulling the data from a separate DB connection, and only one table (for example in table "Novedades"), you don't need the accent graves ( ` ) around the column names, nor do you need the table name in front of the column names, so you'll see that I changed your query from this:

SELECT NOVEDADES.`ID`,
       NOVEDADES.`USUARIO`,
       NOVEDADES.`NO_FORMULARIO`,
       NOVEDADES.`TIPO_NOVEDAD`,
       NOVEDADES.`DES_NOVEDAD`,
       NOVEDADES.`ESTADO`,
       NOVEDADES.`FECHA_NOVEDAD`,
       NOVEDADES.`FECHA_RESOLUCION`
FROM NOVEDADES

To this:

SELECT ID,
       USUARIO,
       NO_FORMULARIO,
       TIPO_NOVEDAD,
       DES_NOVEDAD,
       ESTADO,
       FECHA_NOVEDAD,
       FECHA_RESOLUCION
FROM NOVEDADES

It works fine now. Sorry for the delay, by the way!