Proper Prepare Statement for ALTER TABLE and using AFTER

Question

My code for ALTER TABLE doesn't make use of the prepare() method of $wpdb and so the code needs to be updated properly. There are plenty of examples of query SELECT, etc but couldn't find something for ALTER TABLE with several options included in the SQL.

This is the old code.

$post_qry = $wpdb->get_row( "SELECT * FROM $wpdb->posts" );

if ( ! isset( $post_qry->forum_id ) ) {
    $wpdb->query( "ALTER TABLE {$wpdb->posts} ADD `forum_id` INT( 10 )
        UNSIGNED NOT NULL DEFAULT '0' AFTER `ID` " );
}

This is my first attempt, but something doesn't look right for the ADD.

if ( ! isset( $post_qry->forum_id ) ) {
    $wpdb->query( $wpdb->prepare( "ALTER TABLE {$wpdb->posts} ADD col= %s INT( 10 )
        UNSIGNED NOT NULL DEFAULT '0' AFTER col = %s ", 'forum_id', 'ID' ) );
}

• First, is it proper to use ADD col = or is it ADD COLUMN=%s ?

• Second, is the same true for stating after col=%s?

• Third, should INT and UNSIGNED be used as %s also?

Thank you for your time to explain and maybe point to a good resource.

Answer 1

Answer to this question actually comes from @TomJNowell. Instead of using MySQL calls, use the native functions included with WordPress:

update_post_meta ( $post->ID , 'forum_id', $thread_id );

where the forum_id is the key and the $thread_id is the value. I tried add_post_meta but that created duplicates.

To retrieve the meta data

$thread_id = get_post_custom_values( 'thread_id', $post->ID);

Now I'm looking at ways to add to the comment meta. Hopefully this helps someone else.