php - PHP 与 MySQl 中的字符串比较不正确

Question

所以我试图比较今天的日期和数据库中最后一个条目的日期。由于某种原因，代码无法正常工作，并且比较总是错误的。

$recentMood = mysqli_query($db_connection, "SELECT * FROM DemoUser ORDER BY date DESC LIMIT 1'");

   $today = date('Y-m-d');



   if($recentMood['date'] != $today){
      mysqli_query($db_connection, "INSERT INTO DemoUser (Mood, date) VALUES('$mood' , NOW())");
      echo "Mood recorded!";
   }

   else{


   echo "Mood already recorded.";
   }

P.S:当我尝试回显 $today 或 $recentMood['date'] 时，我得到一个错误。这是什么原因？

Answer 1

您在 if 内部将资源与日期字符串进行比较。

if($recentMood['date'] != $today){

先获取结果:

$query = mysqli_query($db_connection, "SELECT * FROM DemoUser ORDER BY date DESC LIMIT 1");
if($query->num_rows > 0) {
    $recentMood = $query->fetch_assoc(); // fetch it, you skipped this step
    $today = date('Y-m-d');

    $mood = $db_connection->real_escape_string($mood);
    if($recentMood['date'] != $today){
      mysqli_query($db_connection, "INSERT INTO DemoUser (Mood, date) VALUES('$mood' , NOW())");
      echo "Mood recorded!";
    } else {
        echo "Mood already recorded.";
    }
}