pdo操作数据的步骤

$pdo = new PDO('mysql:dbname=php','root','root');

$sql = "SELECT name,email FROM user WHERE user_id < :user_id";

$stmt = $pdo->prepare($sql);

$user_id = 5;

$stmt->bindParam(':user_id',$user_id,PDO::PARAM_INT);

stmt->setFetchMode(PDO::FETCH_ASSOC);

$row = $stmt->fetch();

$row = $stmt->fetch(PDO::FETCH_ASSOC);

var_export($row); //字符串方式输出

echo '<br>';

fetch()会将记录指针自动下移

$row = $stmt->fetch(PDO::FETCH_ASSOC);

var_export($row); //字符串方式输出

echo '<hr>';

while($row=$stmt->fetch(PDO::FETCH_ASSOC)) {

   var_export($row); //字符串方式输出

   echo '<br>';

}