代碼如下：
//$conn = new mysqli($sql_server_name, $sql_username, $sql_password, $sql_db);
$timu = $_GET["timu"];
$sql = $conn->query("查詢 * from problems where timu
='". $timu . "'"); // 從problems庫裏查 註意把“查詢”改成“select”，因為百度知道會屏蔽sql語句
if (mysqli_fetch_assoc($sql) > 0) {
echo "已存在";
} else {
echo "不存在";
}