public function set_query() {

		global $wpdb;

		$dates = $this->get_posted_dates();

		$student_ids = '';
		$students    = $this->get_posted_students();
		if ( $students ) {
			$student_ids .= 'AND ID IN ( ' . implode( ', ', $students ) . ' )';
		}

		$this->query_function = 'get_results';
		$this->output_type    = OBJECT;

		$this->query = "SELECT user_registered AS date
						FROM {$wpdb->users}
						WHERE
							user_registered BETWEEN CAST( %s AS DATETIME ) AND CAST( %s AS  DATETIME )
							{$student_ids}
						;";

		$this->query_vars = array(
			$this->format_date( $dates['start'], 'start' ),
			$this->format_date( $dates['end'], 'end' ),
		);

	}