在我的 php 操作文件中,我想检查变量 $class_number 是否已经在名为 CLASS NO 的 MySql 表列中。
$class_number = $_POST['class'];
echo $class_number;
$check_class_number = mysqli_query($con, "SELECT * FROM Academy.COLUMNS
WHERE ClassNumber = '$class_number' ");
if(count($check_class_number)>0){
echo "exists";
}
else{
echo "It does not exist.";
}
尝试以下操作:
$result = mysqli_query($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
}