我这样写也可以返回关联数组
<?php header('content-type:text/html;charset=utf-8'); error_reporting(E_ALL^E_NOTICE); try { $pdo=new PDO('mysql:host=localhost;dbname=imooc', 'root', 'root'); $sql='SELECT * FROM user'; $stmt=$pdo->prepare($sql); $res=$stmt->execute(); if($res){ while($row=$stmt->fetch(MYSQL_ASSOC)){ print_r($row); echo'<br/>'; } } }catch (PDOException $e){ echo $e->getMessage(); }