通过分组匹配值来循环数组

Question

我正在为我的网站编写一个模块，它给出了测试结果的细目，我需要得到一些类似的东西，

测试标题

平均分数85%测试题目2

平均马克12%

我从数据库中得到的数组如下所示，

    Array
(
    [0] => Array
        (
            [result_id] => 11
            [test_taken] => 2011-10-04 16:22:59
            [mark] => 5
            [retaken] => false
            [tests_test_id] => 4
            [test_title] => Website Development CSS Basics
            [test_slug] => website-development-css-basics
            [mark_needed] => 90
            [retake] => Yes
            [topic_id] => 402
            [topics_topic_id] => 402
        )

    [1] => Array
        (
            [result_id] => 12
            [test_taken] => 2011-10-04 16:30:02
            [mark] => 50
            [retaken] => false
            [tests_test_id] => 5
            [test_title] => Another Test
            [test_slug] => another-test
            [mark_needed] => 10
            [retake] => No
            [topic_id] => 402
            [topics_topic_id] => 402
        )

)

这是我目前的查询，

$this->db->select('results.result_id, results.test_taken, results.mark, results.retaken, results.tests_test_id, tests.test_title, tests.test_slug, tests.mark_needed, tests.retake, topics.topic_id, tests.topics_topic_id')
    ->from('results')
    ->join('tests', 'tests.test_id = results.tests_test_id', 'left')
    ->join('topics', 'topics.topic_id = tests.topics_topic_id', 'left');

    $query = $this->db->get();
    return $query->result_array();

我需要以某种方式将所有的结果分组--有相同的测试id --这样我就可以使用标记键得到结果的平均值。

这在PHP中是可能的吗？

Answer 1

这就是你应该让数据库为你做的事情。与…有关的东西：

SELECT AVG(mark) FROM test_results GROUP BY tests_test_id

Answer 2

创建一个新的数组，然后循环-添加吗？

$sumArray = array();

foreach ($myArray as $key=>$val) {
    $sumArray[$key]+=$val;
}

print_r($sumArray['test_id']);