How do I join the the tables related to the current user to retrieve the information from another table in a shortcode?

Question

I have being trying to create a shortcode to retrieve the information from the csld_events and output in a certificate, but it turnout it is returning every event related to the course_id in the csld_events.

In this situation I could not find a way to only select the events related to the current user, i thought maybe i should try to retrieve it also with the group-id that the course and the student is registered, but until the moment i could not find any way to relate the three of them and be able to retrieve from csld_events the event with course id(object_id) and group id(ld_group).

In the wp_posts table i could find the posts related to group but nothing that would relate them to the course or the users in that group.

In the wp_learndash_user_activity i could find the activity_status with group-progress as meta-value with the post_id which is also the group ID but nothing that would relate it to the course.

Did anybody go through something like this in wordpress + learndash and have a solution for it?

<?php

// Function to retrieve the dates of a course for a specific user
function get_course_dates( $user_id, $course_id ) {
    // Retrieve the dates of the course
    global $wpdb;
    $table_name = $wpdb->prefix . 'csld_events';
    $query = $wpdb->prepare( "SELECT start, end FROM $table_name WHERE object_id = %d", $course_id );
    $course_dates = $wpdb->get_results( $query, ARRAY_A );
    // Return the course dates
    return $course_dates;
  }
  
  // Register the shortcode to show the course dates
  add_shortcode( 'course_dates', 'course_dates_shortcode' );
  function course_dates_shortcode( $atts ) {
    // Extract the attributes
    $atts = shortcode_atts( array(
      'user_id' => 0,
      'course_id' => 0
    ), $atts, 'course_dates' );
  
    // If the user ID is not specified, use the current user
    $user_id = $atts['user_id'];
    if ( !$user_id ) {
      $user_id = get_current_user_id();
    }
  
    // Retrieve the course dates for the user
    $course_dates = get_course_dates( $user_id, $atts['course_id'] );
  
    // Build the output for the shortcode
    $output = '';
    if ( !empty( $course_dates ) ) {
      $output .= '<ul>';
      foreach ( $course_dates as $date ) {
        $start = date_create($date['start']);
        $end = date_create($date['end']);
        $output .= '<p>Start: ' . date_format($start,'d/m/Y') . '<br>Eind: ' . date_format($end,'d/m/Y') . '</p>';
      }
      $output .= '</p>';
    }
  
    // Return the output of the shortcode
    return $output;
  }
  ?>