<分区>
我试图让用户根据名称、价格等对 mysql 查询进行排序。这个下拉菜单赋予他们这样做的能力，它根据用户的选择更改“ORDER BY”子句。现在是凌晨 3 点，我就是找不到错误:
<?php
$sortBy = $_POST['sortBy'];
if ($sortBy) {
$priceLowToHigh = $_POST['price-low-to-high'];
$priceHighToLow = $_POST['price-high-to-low'];
$dateMostRecent = $_POST['date-most-recent'];
$dateOldest = $_POST['date-oldest'];
$alphabeticalOrder = $_POST['alphabetical-order'];
if ($priceLowToHigh) {
$sortOrder = "price ASC";
} elseif ($priceHighToLow) {
$sortOrder = "price DESC";
} elseif ($dateMostRecent) {
$sortOrder = "date DESC";
} elseif ($dateOldest) {
$sortOrder = "date ASC";
} elseif ($alphabeticalOrder) {
$sortOrder = "name ASC";
}
} else {
$sortOrder = "date DESC";
}
?>
<form action="" method="post">
<select name="sortBy" onchange="this.form.submit()">
<option>Sort By</option>
<option value="price-low-to-high">Price (low to high)</option>
<option value="price-high-to-low">Price (high to low)</option>
<option value="date-most-recent">Date (most recent)</option>
<option value="date-oldest">Date (oldest)</option>
<option value="alphabetical-order">Alphabetical Order</option>
</select>
</form>
后面的 ORDER BY 子句是这样使用的:
$query = mysql_query("SELECT * FROM products WHERE category = $categoryId ORDER BY $sortOrder");