PDO连续查询mysql出现找不到execute()函数

[wangjian727924]

$db = new PDO($db_config['dsn'],$db_config['username'],$db_config['password']);//建立连接
$db->exec('SET NAMES '.C('DB_CHARSET'));
$sql = "select * from tab limit 1";
$sth = $db->prepare($sql);
$sth->execute();
$result = $sth->fetch();
print_r($result);//此处数据可以查询出来
$sql = "select * from tab limit 2";
$sth = $db->prepare($sql);
$sth->execute();//程序执行到此处就会报错
$sth->fetchAll();
dump($result);
报错信息：Fatal error: Call to a member function execute() on a non-object in

[wangjian727924]

[mailangel123]

php 与pdo 数据库连接实例
http://www.111cn.net/phper/21/pdo_php.htm

[lizhong8532]

我也遇到此问题

[纸牌屋弗兰克]

官方示例：

<?php
/* Execute a prepared statement by passing an array of values */
$sql = 'SELECT name, colour, calories
    FROM fruit
    WHERE calories < :calories AND colour = :colour';
$sth = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
$sth->execute(array(':calories' => 150, ':colour' => 'red'));
$red = $sth->fetchAll();
$sth->execute(array('calories' => 175, 'colour' => 'yellow'));
$yellow = $sth->fetchAll();
?>

[纸牌屋弗兰克]

你是什么问题找到了吗，找到了回复我，我也不知道

[纸牌屋弗兰克]

由此可见，prepare主要用来执行绑定参数的sql语句，你不能分别弄一个sql语句，分别弄一个prepare