PHP 分组和循环

Question

我如何按技能对其进行分组并回显每项技能的所有照片。

SELECT skills.teacher, skills.student, skills.skill, profile.photo
FROM skills
INNER JOIN profile ON skills.student = profile.username
WHERE teacher =  'teach1'

teacher | student  | skill  | photo
------- | -------- | ------ | ------------
teach1  | student1 | skill1 | student1.jpg
teach1  | student2 | skill1 | student2.jpg
teach1  | student3 | skill2 | student3.jpg
teach1  | student3 | skill1 | student3.jpg
teach1  | student4 | skill3 | student4.jpg
teach1  | student1 | skill2 | student1.jpg

我强调这是一个例子。我实际上不知道“技能”的名称，因为它们是学生们创造的。不知道总共会列出多少技能。我不知道哪些用户会给哪些老师添加哪些技能。

我尝试过 while 循环和 foreach 循环。我只是不知道如何对其进行分组以及使用什么类型的循环...

我需要我的最终结果来让我 echo 。

<div>skill1 
 <img src="student1.jpg">
 <img src="student2.jpg">
 <img src="student3.jpg">
 ...
 ...
 ...
</div>

<div>skill2
 <img src="student1.jpg">
 <img src="student3.jpg">
 ...
 ...
 ...
</div>

 <div>skill3
 <img src="student4.jpg">
 ...
 ...
 ...
</div>

Answer 1

首先，按技能排序，以便按顺序排列它们:

SELECT skills.teacher, skills.student, skills.skill, profile.photo
FROM skills
INNER JOIN profile ON skills.student = profile.username
WHERE teacher =  'teach1'
ORDER BY skills.skill

在 while 循环之外分配一个变量(在本例中为 $lastSkill)。检查它是否改变，并相应地输出内容。看看下面的例子。您的 PHP 代码看起来与此类似:

$lastSkill = null;

while ( $row = fetchrow() )
{
    if ( $row['skill'] !== $lastSkill )
    {
        //Don't close a div, if it's the first row
        if ( $lastSkill !== null )
            echo '</div>';

        //We've moved onto a new row, echo it out
        echo '<div>' . $row['skill'];
        //Store the lastSkill
        $lastSkill = $row['skill'];
    }

    echo '<img src="' . $row['photo'] . '">';
}