diff --git a/mod/quiz/report/attemptsreport.php b/mod/quiz/report/attemptsreport.php
index fc259a226da..58163af3926 100644
--- a/mod/quiz/report/attemptsreport.php
+++ b/mod/quiz/report/attemptsreport.php
@@ -352,7 +352,7 @@ abstract class quiz_attempts_report extends quiz_default_report {
                          WHERE {$allowedjoins->wheres} AND quiza.id = :attemptid";
             }
             $params = $allowedjoins->params + array('attemptid' => $attemptid);
-            $attempt = $DB->get_record_sql($sql, $params);
+            $attempt = $DB->get_record_sql($sql, $params, IGNORE_MULTIPLE);
             if (!$attempt || $attempt->quiz != $quiz->id || $attempt->preview != 0) {
                 // Ensure the attempt exists, belongs to this quiz and belongs to
                 // a student included in the report. If not skip.
diff --git a/mod/quiz/report/overview/tests/helpers.php b/mod/quiz/report/overview/tests/helpers.php
new file mode 100644
index 00000000000..50a36507936
--- /dev/null
+++ b/mod/quiz/report/overview/tests/helpers.php
@@ -0,0 +1,59 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Makes some protected methods of quiz_attempts_report public to facilitate testing.
+ *
+ * @package   quiz_overview
+ * @copyright 2020 Huong Nguyen <huongnv13@gmail.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+global $CFG;
+require_once($CFG->dirroot . '/mod/quiz/report/attemptsreport.php');
+
+/**
+ * Makes some protected methods of quiz_attempts_report public to facilitate testing.
+ *
+ * @copyright 2020 Huong Nguyen <huongnv13@gmail.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class testable_quiz_attempts_report extends quiz_attempts_report {
+
+    /**
+     * Override this function to displays the report.
+     * @param object $cm the course-module for this quiz.
+     * @param object $course the course we are in.
+     * @param object $quiz this quiz.
+     */
+    public function display($cm, $course, $quiz) {
+
+    }
+
+    /**
+     * Testable delete_selected_attempts function.
+     *
+     * @param object $quiz
+     * @param object $cm
+     * @param array $attemptids
+     * @param \core\dml\sql_join $allowedjoins
+     */
+    public function delete_selected_attempts($quiz, $cm, $attemptids, \core\dml\sql_join $allowedjoins) {
+        parent::delete_selected_attempts($quiz, $cm, $attemptids, $allowedjoins);
+    }
+}
diff --git a/mod/quiz/report/overview/tests/report_test.php b/mod/quiz/report/overview/tests/report_test.php
index 41fd57dfed6..20a632a4cda 100644
--- a/mod/quiz/report/overview/tests/report_test.php
+++ b/mod/quiz/report/overview/tests/report_test.php
@@ -29,6 +29,7 @@ require_once($CFG->dirroot . '/mod/quiz/locallib.php');
 require_once($CFG->dirroot . '/mod/quiz/report/reportlib.php');
 require_once($CFG->dirroot . '/mod/quiz/report/default.php');
 require_once($CFG->dirroot . '/mod/quiz/report/overview/report.php');
+require_once($CFG->dirroot . '/mod/quiz/report/overview/tests/helpers.php');
 
 
 /**
@@ -263,4 +264,54 @@ class quiz_overview_report_testcase extends advanced_testcase {
         $this->assertEquals($expected, quiz_overview_report::get_bands_count_and_width($quiz));
     }
 
+    /**
+     * Test delete_selected_attempts function.
+     */
+    public function test_delete_selected_attempts() {
+        $this->resetAfterTest(true);
+
+        $timestamp = 1234567890;
+        $timestart = $timestamp + 3600;
+
+        // Create a course and a quiz.
+        $generator = $this->getDataGenerator();
+        $course = $generator->create_course();
+        $quizgenerator = $generator->get_plugin_generator('mod_quiz');
+        $quiz = $quizgenerator->create_instance([
+                'course' => $course->id,
+                'grademethod' => QUIZ_GRADEHIGHEST,
+                'grade' => 100.0,
+                'sumgrades' => 10.0,
+                'attempts' => 10
+        ]);
+
+        // Add one question.
+        $questiongenerator = $this->getDataGenerator()->get_plugin_generator('core_question');
+        $cat = $questiongenerator->create_question_category();
+        $q = $questiongenerator->create_question('essay', 'plain', ['category' => $cat->id]);
+        quiz_add_quiz_question($q->id, $quiz, 0 , 10);
+
+        // Create student and enrol them in the course.
+        // Note: we create two enrolments, to test the problem reported in MDL-67942.
+        $student = $generator->create_user();
+        $generator->enrol_user($student->id, $course->id);
+        $generator->enrol_user($student->id, $course->id, null, 'self');
+
+        $context = context_module::instance($quiz->cmid);
+        $cm = get_coursemodule_from_id('quiz', $quiz->cmid);
+        $allowedjoins = get_enrolled_with_capabilities_join($context, '', ['mod/quiz:attempt', 'mod/quiz:reviewmyattempts']);
+        $quizattemptsreport = new testable_quiz_attempts_report();
+
+        // Create the new attempt and initialize the question sessions.
+        $quizobj = quiz::create($quiz->id, $student->id);
+        $quba = question_engine::make_questions_usage_by_activity('mod_quiz', $quizobj->get_context());
+        $quba->set_preferred_behaviour($quizobj->get_quiz()->preferredbehaviour);
+        $attempt = quiz_create_attempt($quizobj, 1, null, $timestart, false, $student->id);
+        $attempt = quiz_start_new_attempt($quizobj, $quba, $attempt, 1, $timestamp);
+        $attempt = quiz_attempt_save_started($quizobj, $quba, $attempt);
+
+        // Delete the student's attempt.
+        $quizattemptsreport->delete_selected_attempts($quiz, $cm, [$attempt->id], $allowedjoins);
+    }
+
 }