php - 使用 PHP 将数字添加到 MySql 值

Question

我使用以下 PHP 将 MySql 数据库中的表值加 1，并在每次执行代码时更新数据库。

function create_update() {
    $user_id = $_SESSION['user_id'];
    $con = mysqli_connect(HOST, USER, PASSWORD, DATABASE);
    if (mysqli_connect_errno()) {
        echo "Failed to connect to MySQL: " . mysqli_connect_error();
    }

    $numberofupdates = number_of_updates(); //'number_of_updates()' gets an INT from the database
    settype($numberofupdates, "integer"); //set the number to an INT if it already is not
    $spare_update_id = $numberofupdates + 1; //get number and add 1
    mysqli_query($con,"UPDATE members SET updates=$spare_update_id WHERE id = $user_id"); //update the value to the database
}

代码工作正常并更新到数据库，但似乎每次都会将值更新为 1。如果我手动将数据库值设置为 4 并运行代码，它会将该值设置回 1，而该值应该是 5。

感谢任何帮助!

Answer 1

如果我正确理解你的问题，你只需要 1 个 mysql 查询

function create_update() {
  $user_id = $_SESSION['user_id'];
  $con = mysqli_connect(HOST, USER, PASSWORD, DATABASE);
  if (mysqli_connect_errno()) {
      echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }
  mysqli_query($con,"UPDATE members SET updates = (updates + 1) WHERE id = $user_id");
}