PHP:使用 optgroup 进行动态下拉

Question

我正在开发一个下拉菜单，该菜单使用 HTML optgroups 作为员工所属的组名称。这是 MySQL 查询和输出:

mysql> SELECT employees.emp_id,employees.empname,employees.grp_id,groups.groupname FROM employees left join groups on employees.grp_id = groups.grp_id order by groupname asc;
+--------+------------+--------+-----------+
| emp_id | empname    | grp_id | groupname |
+--------+------------+--------+-----------+
|     20 | Employee 2 |     13 | Group 1   |
|     19 | Employee 1 |     13 | Group 1   |
|     21 | Employee 3 |     14 | Group 2   |
+--------+------------+--------+-----------+
3 rows in set (0.00 sec)

The only issue is, I'm having the hardest time figuring out how to get the optgroup to work correctly. I've tried countless times, and it's really starting to frustrate me. The following is pretty much I want the output to be (example):

<select name="dropdownmenu">
    <optgroup label="Group 1">
        <option name="20">Employee 2</option>
        <option name="19">Employee 1</option>
    </optgroup>
    <optgroup label="Group 2">
        <option name="21">Employee 3</option>
    </optgroup>
</select>

基本上，optgroup 需要是“groupname”，选项“name”应该是“emp_id”，操作“option”(下拉项)是“empname”。

我希望这是可以做到的事情，但真的不确定。这是我拥有的功能，但它并不完全有效:

function getDynGrpList() {
    global $db;

    // $query = "SELECT * FROM employees ORDER BY grp_id desc;";
    $query = "SELECT employees.emp_id,employees.empname,employees.grp_id,groups.groupname FROM employees left join groups on employees.grp_id = groups.grp_id order by groupname asc;";
    $employees = $db->GetAll($query);
    $groups = array();

    while ($qa = $employees->GetRows()) {
        $groups[$qa['groupname']][$qa['grp_id']] = $qa['empname'];
    }
    foreach ($groups as $label => $opt) { ?>
        <optgroup label="<?php echo $label; ?>">
<?php   }
        foreach ($groups[$label] as $id => $name) { ?>
            <option value="<?php echo $id; ?>"><?php echo $name; ?></option>
<?php } ?>
        </optgroup>
<?php }

getDynGrpList 函数截至凌晨 3:15 CST (2/27):

function getDynGrpList() {
    global $db;

    // $query = "SELECT * FROM employees ORDER BY grp_id desc;";
    $query = "SELECT employees.emp_id,employees.empname,employees.grp_id,groups.groupname FROM employees left join groups on employees.grp_id = groups.grp_id order by groupname asc;";
    $employees = $db->GetAll($query);
    $groups = array();
    while ($qa = $employees->GetRows()) {
        $groups[$qa['groupname']][$qa['emp_id']] = $qa['empname'];
    }
    var_export($groups);
    foreach($groups as $label => $opt): ?>
        <optgroup label="<?php echo $label; ?>">
    <?php foreach ($opt as $id => $name): ?>
        <option value="<?php echo $id; ?>"><?php echo $name; ?></option>
    <?php endforeach; ?>
    </optgroup>
<?php endforeach;
}

最终解决方案(在 Felix Kling 的帮助下)

function getDynGrpList() {
    global $db;

    $query = "SELECT employees.emp_id,employees.empname,employees.grp_id,groups.groupname FROM employees left join groups on employees.grp_id = groups.grp_id order by groupname asc;";
    $employees = $db->GetAll($query);
    $groups = array();
    foreach ($employees as $employee) {
        $groups[$employee['groupname']][$employee['emp_id']] = $employee['empname'];
    }
    foreach($groups as $label => $opt): ?>
        <optgroup label="<?php echo $label; ?>">
    <?php foreach ($opt as $id => $name): ?>
        <option value="<?php echo $id; ?>"><?php echo $name; ?></option>
    <?php endforeach; ?>
    </optgroup>
<?php endforeach;
}

Answer 1

这两个 for 循环没有嵌套在您的代码中:

foreach ($groups as $label => $opt) { ?>
    <optgroup label="<?php echo $label; ?>">
<?php   } <-- wrong here
    foreach ($groups[$label] as $id => $name) { ?>
        <option value="<?php echo $id; ?>"><?php echo $name; ?></option>
<?php } ?>

结果是首先创建所有 opt 组，然后添加最后一个组的员工(因为 $label 和 $opt 在循环后也可用完成)。

您必须嵌套循环( using alternative syntax for control structures ):

<?php foreach($groups as $label => $opt): ?>
    <optgroup label="<?php echo $label; ?>">
    <?php foreach ($opt as $id => $name): ?>
        <option value="<?php echo $id; ?>"><?php echo $name; ?></option>
    <?php endforeach; ?>
    </optgroup>
<?php endforeach; ?>

此外，我认为创建数组时必须使用 emp_id，而不是 grp_id:

while ($qa = $employees->GetRows()) {
    $groups[$qa['groupname']][$qa['emp_id']] = $qa['empname'];
}