PHP - mysqli_query计数总是返回1 [重复]

I am a kind of a beginner in this ...

For some reason This mysqli_query count always returns 1

$class_number = $_POST['class'];

$check_class_number = mysqli_query($con, " SELECT * FROM `Academy` WHERE ClassNumber = '".$class_number."' ");

echo count($check_class_number);

The current situation in my MySql table:

1- I have only two rows

2- Under the column ClassNumber I have the same value 150701-100

I simply need to count the number of the ClassNumber 150701-100, which suppose in my case to returns 2. However as I mentions it always returns 1, even if I added more rows.

My final intention is to add this logical if to the code

 if(count($check_class_number)>0){
                  echo "exists.";

                  }else{
                  echo "It does not exist.";

                  }

Your help is much appreciated.

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Use mysqli_num_rows to count the number of rows returned from the query. count() will only work on an array.

 if(mysqli_num_rows($check_class_number)>0) {
      echo "exists.";
 } else {
      echo "It does not exist.";
 }

you can do as OllyTenerife, or use $check_class_number to get the num of rows.

if($check_class_number->num_rows > 0)
{
     doSmt();
}
else
{
    echo "Does not exist.";
}