<code>$pdo=new PDO("mysql:host=localhost;dbname=t1","root","");
$txt=$_POST["txt"];
$sql="insert into user(txt)values($txt)";
$pdo->exec($sql);</code><code>$pdo=new PDO("mysql:host=localhost;dbname=t1","root","");
$txt=$_POST["txt"];
$sql="insert into user(txt)values($txt)";
$pdo->exec($sql);</code>
<code>$sql="insert into user(txt)values('$txt')";</code>你的txt应该是字符串类型的字段，记得加单引号
没有什么错误提示么？换种写法试试
<code>// 预处理 $sql = "INSERT INTO `user`(`txt`) VALUES (:txt)"; $stmt = $pdo->prepare($sql); $stmt->execute([':txt' => $txt]);</code>
