无法获取重复的行PHP

Question

My code is running for first time perfectly (if & else condition), next time if i execute this code, it is not executing if conditon.Dont know why. Can someone have a look at this. Its is checking the hash value in DB if found do nothing else insert row, but it is duplicating rows.

$data = array();
foreach($objJson["statuses"] as $status) {
  $data[] = array("created_at" => $status["created_at"],"text" => $status["text"],"user_img" => $status["user"]["profile_image_url"],"from_user" => $status["user"]["screen_name"],"id" => $status["id"],"media_url" => $status["entities"]["media"][0]["media_url_https"],"hash" => md5($status["created_at"].$status["text"].$status["user"]["screen_name"]));

  $check2 = "SELECT hash FROM tweets where hash=".md5($status["created_at"].$status["text"].$status["user"]["screen_name"])." ";
  $res=mysqli_query($con,$check2);

  if (mysqli_num_rows($res)==1) {

  }
  else
  {
    $check = "INSERT INTO tweets (`created_at`,`text`,`user_img`,`from_user`,`media_url`,`hash`) 
VALUES('".$status["created_at"]."','".$status["text"]."','".$status["user"]["profile_image_url"]."','".$status["user"]["screen_name"]."','".$status["entities"]["media"][0]["media_url_https"]."','".md5($status["created_at"].$status["text"].$status["user"]["screen_name"])."')";
mysqli_query($con,$check);
  }
}

Answer 1

Try this code. I improved the formatting and saw that quotes were missing around the hash, a minor problem:

foreach($objJson["statuses"] as $status) {
  $hash   = md5($status["created_at"].$status["text"].$status["user"]["screen_name"]));
  $check  = "SELECT hash FROM tweets WHERE hash = '$hash'";
  $result = mysqli_query($con,$check);
  if (mysqli_num_rows($result) == 0) {
    $insert = "INSERT INTO tweets (created_at,text,user_img,from_user,media_url,hash) 
               VALUES('".$status["created_at"]."','".
                         $status["text"]."','".
                         $status["user"]["profile_image_url"]."','".
                         $status["user"]["screen_name"]."','".
                         $status["entities"]["media"][0]["media_url_https"]."','".
                         $hash."')";
    mysqli_query($con,$insert);
  }
}

I also improved the structure of your code a bit.