Check if form-posted variable is existing in one of MySql columns [closed]

Answer 1

Give the following a try:

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

if(mysqli_num_rows($result) == 0) {
    // the number does not exist so do whatever you wish
} else {
    // post an error message
}

Answer 2

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

if(count($check_class_number)>0){
    echo "exists";
 //do whatever you want to do
}
else{
  echo "It does not exist.";
}

Answer 3

use the mysqli_num_rows property.

if( $check_class_number->num_rows > 0 ){
//yes
} else {
//no
}