php - 如果单元格为空插入语法

Question

我正在尝试检查候选人表中的专业、年级和大学是否为空，如果是，则插入大学...否则... 我的语法合适吗？

$sqlCheck1 = "SELECT `Major`, `Grade`, `University` FROM Candidates WHERE ID='".$_GET["cid"]."'";

                $result5 = mysqli_query($con,$sqlCheck1);


                while($row5 = mysqli_fetch_array($result5)) {

                    $major = $row5['Major'];
                    $grade = $row5['Grade'];
                    $university = $row5['University'];

                if (mysqli_num_rows($result5) == 0) 
        {
           $sql5 = "INSERT INTO `university` (`major`, `degree`, `univ`, `afnumber`) VALUES ('$major','$grade','$university','".$_GET["af"]."')";
            if (mysqli_query($con,$sql5) === TRUE) {
                    } else {
                    echo "Error: " . $sql5 . "<br>" . mysqli_error($con);
                    }

        }
else 
    {

Answer 1

使用下面的代码

$sqlCheck1 = "SELECT `Major`, `Grade`, `University` FROM Candidates WHERE ID='".$_GET["cid"]."'";
            $result5 = mysqli_query($con,$sqlCheck1);
            if (mysqli_num_rows($result5) == 0) 
    {
       $sql5 = "INSERT INTO `university` (`major`, `degree`, `univ`, `afnumber`) VALUES ('$major','$grade','$university','".$_GET["af"]."')";
        if (mysqli_query($con,$sql5) === TRUE) {
                } else {
                echo "Error: " . $sql5 . "<br>" . mysqli_error($con);
                }

    }
else 
    {