如何基于存储在数据库中的值在选择菜单中预先选择一个选项？

Question

I have a number of dropdown lists, which update a database, however once updated the first object on the list is displayed, rather than the actual object selected. What is the best way to fix this?

Code sample: HTML code sample

<select name="sleeps">
       <option value="0">Sleeps</option>
       <option value='1'>1</option>
       <option value='2'>2</option>
       <option value='3'>3</option>
       <option value='4'>4</option>
</select>

This is generated using:

 <?php 
                                for ($x = 1; $x <=10; $x++) {
                                    echo "<option value='$x'>$x</option>";
                                }
?>

Desired result

 <select name="sleeps">
       <option value="0">Sleeps</option>
       <option value='1'>1</option>
       <option value='2'>2</option>
       <option value='3'>3</option>
       <option value='4' selected>4</option>
</select>

Answer 1

        for ($x = 1; $x <=10; $x++) {
            $sel = ($x == $the_value) ? " selected='selected'" : "";
            echo "<option value='$x'$sel>$x</option>";
        }

For the record, mixing your PHP and HTML like this is very messy and not easily maintained.

Edit: Since you're likely new to PHP, I should mention this is called the ternary operator which is just a shorthand way of writing an if statement.

Answer 2

Figured it out :)

Note - $echo and $title are there to allow changes in order to allow flexibility.

function select_dropdown($sql, $echo, $title) {
include 'connect.php';
$id = $_GET['id'];
$select = $conn->prepare($sql);
$select->bind_param('s', $id);
$select->execute();
$select->store_result();
if ($select->num_rows > 0) {
    $meta = $select->result_metadata();
echo "<select name='$title'>
                        <option value='0'>$title</option>\n";
    while ($field = $meta->fetch_field()) {
        $params[] = &$row[$field->name];
    }
    call_user_func_array(array($select, 'bind_result'), $params);
    while ($select->fetch()) {
                 for ($x = 1; $x <=10; $x++) {
             if ($row[$echo] == $x) {
                 echo "<option value='$row[$echo]' selected>$row[$echo]</option>";
             } else {
             echo "<option value='$x'>$x</option>";
             }
                            }

    }
    $select->close();
    echo "</select>";
}

}