如何根据其他列值输出SQL列？

Question

I have a WordPress database I am working on which stores form data from the Front-end. When submitting these forms, a parent_id is assigned which matches up to the Wordpress post that they sit on.

I am going to export the columns and rows into a CSV depending on the WP ID.

The main issue I am facing is only exporting the columns that have values.

For example, if I exported the CSV on the WP Post of 206 I would need to get all of the columns apart from "Do you want free paper?" and "Male or Female".

    global $post;
    global $wpdb;
    $form_id = $post->ID;
    $title = str_replace(' ', '-', get_the_title($form_id));
    $title = preg_replace('/[^A-Za-z0-9\-]/', '', $title);
    $filename = $title . '.csv';
    $table_answers = $wpdb->prefix . "opforms_sub";
    $output = fopen('php://output', 'w');
    $headers = $wpdb->get_col("DESC wp_opforms_sub", 0);

    fputcsv( $output, $headers);

    header('Content-Type: text/csv; charset=utf-8');
    header("Content-Disposition: attachment; filename=". $filename);

Many thanks in advance!

Answer 1

You could use following query

SELECT column_name FROM information_schema.columns WHERE table_name='wp_opforms_sub' LIMIT 0,7

instead of

DESC wp_opforms_sub

Should be

$headers = $wpdb->get_col("SELECT column_name FROM information_schema.columns WHERE table_name='wp_opforms_sub' LIMIT 0,7", 0);