在使用 MySQLi 写入数据库之前忽略表单中的空白字段

Question

好的，所以问题是，当提交此表单并且有一些输入字段留空时，空白数据将写入数据库，并且因为我不希望每个字段的重复输入第二个填写除非他们将不同的字段留空，否则无法提交。

我不想这样做，所以人们必须填写所有字段，因为不是每个人都会拥有每个字段要求的用户名。

if(isset($_POST["signupbtn"])) {
    if ($log_username) {
        /// getting data from submitted form into local variables
        $x = preg_replace('#[^a-z 0-9]#i', '', $_POST['xbox']);
        $p  = preg_replace('#[^a-z 0-9]#i', '', $_POST['psn']);
        $s = preg_replace('#[^a-z 0-9]#i', '', $_POST['steam']);
        $ip = preg_replace('#[^0-9.]#', '', getenv('REMOTE_ADDR'));
        // DUPLICATE DATA CHECKS FOR GAMER PROFILES
        $sqli = "SELECT username FROM player WHERE xbox='$x' LIMIT 1";
        $query = mysqli_query($db_conx, $sqli); 
        $x_check = mysqli_num_rows($query);
        // -------------------------------------------
        if ($x_check > 0){ 
            echo "Xbox Gamer-Tag already linked to a user on this website";
            exit();
        } else if (is_numeric($x[0])) {
            echo 'Xbox Gamer-Tag cannot begin with a number';
            exit();
        }
        $sqli = "SELECT username FROM player WHERE psn='$p' LIMIT 1";
        $query = mysqli_query($db_conx, $sqli); 
        $p_check = mysqli_num_rows($query);
        // -------------------------------------------
         if ($p_check > 0){ 
            echo "PSN User already linked to a user on this website";
            exit();
        } else if (is_numeric($p[0])) {
            echo 'PSN User cannot begin with a number';
            exit();
        }
        $sqli = "SELECT username FROM player WHERE steam='$s' LIMIT 1";
        $query = mysqli_query($db_conx, $sqli); 
        $s_check = mysqli_num_rows($query);
        // FORM DATA ERROR HANDLING
         if ($s_check > 0){ 
            echo "Steam account already linked to a user on this website";
            exit();
        } else if (is_numeric($s[0])) {
            echo 'Steam account cannot begin with a number';
            exit();
        } else  { $sqli = "INSERT INTO player (id, username, xbox, psn, steam, ip, created, lastupdated, notecheck)        
                VALUES ('$id','$log_username','$x','$p','$s','$ip',NOW(),NOW(),NOW())"; 
                $query = mysqli_query($db_conx, $sqli);
                   echo "Gamer Profiles Updated";
                }   

        exit();

            if (!file_exists("p_player/$log_username")) {
                mkdir("p_player/$log_username", 0755);
            } 


     }


}

上面是 php，它工作正常，它将信息写入表没有问题，除了它还将空白数据写入数据库的事实。如果有人能指出我正确的方向，甚至解决我的问题，我将不胜感激。我已经查看了整个谷歌，但似乎找不到任何东西，因为我找到的所有答案都不完全是我的意思，而且由于我是 PHP 新手，因此任务似乎更难找到我正在寻找的正确答案.感谢您花时间阅读本文。

Answer 1

您仍然可以允许多个 NULL 值。将这些唯一列设置为具有默认值NULL，因此如果没有传递任何内容，它将存储NULL 而不是空值。

Answer 2

你差不多明白了，我会做以下

以蒸汽为例

if ($s != ''){
        $sqli = "SELECT username FROM player WHERE steam='$s' LIMIT 1";
        $query = mysqli_query($db_conx, $sqli); 
        $s_check = mysqli_num_rows($query);
        // FORM DATA ERROR HANDLING
         if ($s_check > 0){ 
            echo "Steam account already linked to a user on this website";
            exit();
        } else if (is_numeric($s[0])) {
            echo 'Steam account cannot begin with a number';
            exit();
        }
} else  { 
                $sqli = "INSERT INTO player (id, username, xbox, psn, steam, ip, created, lastupdated, notecheck)        
                VALUES ('$id','$log_username','$x','$p','$s','$ip',NOW(),NOW(),NOW())"; 
                $query = mysqli_query($db_conx, $sqli);
                   echo "Gamer Profiles Updated";
}   

然后在该字段中允许重复值。这将允许空白字段，但不允许包含数据的重复字段。