Show the user's start date.

my-show-user-start.php

<?php
/**
 * Show the user's start date.
 * Show the user's previously membership start date if they were cancelled, expired or cancelled by an admin.
 * If none of thhe above is found, the string 'nothing found' will be returned.
 */
 
 function my_show_user_startdate() {

	if ( is_user_logged_in() && function_exists( 'pmpro_hasMembershipLevel' ) && pmpro_hasMembershipLevel() ) {
			global $current_user;

		$current_user->membership_level = pmpro_getMembershipLevelForUser( $current_user->ID );
		$user_startdate                 = $current_user->membership_level->startdate;

		if ( ! $user_startdate == 0 ) {
			return date( 'F j, Y', $user_startdate );
		}
	} elseif ( ! pmpro_hasMembershipLevel() ) {
		//try to see if they had a previous membership level.
		global $wpdb, $current_user;

		$sql = "SELECT startdate FROM $wpdb->pmpro_memberships_users WHERE `user_id` = $current_user->ID AND `status` in ('cancelled', 'expired', 'admin_cancelled') ORDER BY startdate ASC LIMIT 1";

		$results = $wpdb->get_results( $sql );

		if ( ! empty( $results[0] ) ) {

			$startdate      = explode( ' ', $results[0]->startdate );
			$user_startdate = strtotime( $startdate[0] );

			return date( 'F j, Y', $user_startdate );

		} else {
			return 'nothing found';
		}
	}
}
add_shortcode( 'show_startdate', 'my_show_user_startdate' );