Remove custom table data when post deleted or updated.

remove_custom_table_data_wordpress

/*
Delete data from custom_table upon deleting the post
*/
add_action( 'admin_init', 'custom_table_admin_init' );
function custom_table_admin_init() {
    add_action( 'delete_post', 'custom_table_data_delete', 10 );
}
 
function custom_table_data_delete( $pid ) {
    global $wpdb;
    $table_name = $wpdb->prefix."custom_table";
    $query = $wpdb->prepare( "SELECT post_id FROM `$table_name` WHERE post_id = %d", $pid );
    $var = $wpdb->get_var( $query );
    if ( $var ) {
        $query2 = $wpdb->prepare( "DELETE FROM `$table_name` WHERE student_id = %d", $pid );
        $wpdb->query( $query2 );
    }
}