//truncate table user; //不但将数据全部删除，而且重新定位自增的字段
<?php
try {
    $pdo = new PDO('mysql:host=localhost;dbname=test', 'root', '');
    //exec():执行一条sql语句并返回其受影响的记录的条数
    //EXEC对于select没有作用
    $sql = 'INSERT user(username,password,email) VALUES("KING","' . md5('king') . '","imooc@qq.com");';
    $res = $pdo->exec($sql);
    echo $res;//1
} catch (PDOException $e) {
    echo $e->getMessage();
}

?>

$pdo->lastInsertId()

<?php
header("content-type:text/html;charset=utf-8");
try {
    $pdo = new PDO('mysql:host=localhost;dbname=test', 'root', '');
    $sql = <<<EOF
    INSERT user(username,password,email)VALUES("king71","king1","imoooc1@qq.com"),
    ("king82","king2","imoooc2@qq.com"),
    ("king93","king3","imoooc3@qq.com");
EOF;
    $res = $pdo->exec($sql);
    echo "受影响的记录的条数:" . $res . "<br/>";
    //lstInsertId 得到新插入记录的ID号
    echo "最后插入的ID号为" . $pdo->lastInsertId();

} catch (PDOException $e) {
    echo $e->getMessage();
}

?>

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