Question

我正在努力应对fetchAll（）的怪异行为。我正在使用PDO执行存储过程，返回歌曲集。

这是我的PHP代码

    $sql = "call getHymn(?)";
    $param = array($id);
    $result = $this->db->getData($sql,$param);

这是getData函数

public function getData($sql,$param=[])
{
    try
    {
        $stmt = $this->connection->prepare($sql);
        $stmt->execute($param);
        echo '<pre>';
        print_r($stmt->fetchAll());
        /*return($stmt->fetchAll());*/
    }
    catch (PDOException $e)
    {
        throw new Exception($e->getMessage());
    }
}

当我在MySQL中执行存储过程时，它会按预期返回3行。但是当我通过PDO执行它并使用fetchall（）然后我在数组外部得到额外的null ..在任何地方都找不到任何帮助，甚至在PHP文档中都没有。我的fetchAll（）输出如下所示

Array
(
[0] => Array
    (
        [id] => 4
        [refrain] => 
        [stanzaId] => 1
        [stanzaText] => Amazing grace! How sweet the sound 
that saved a wretch like me! 
I once was lost, but now am found; 
was blind, but now I see.
    )

[1] => Array
    (
        [id] => 4
        [refrain] => 
        [stanzaId] => 2
        [stanzaText] => 'Twas grace that taught my heart to fear, 
and grace my fears relieved; 
how precious did that grace appear 
the hour I first believed.
    )

[2] => Array
    (
        [id] => 4
        [refrain] => 
        [stanzaId] => 3
        [stanzaText] => Through many dangers, toils, and snares, 
I have already come; 
'tis grace hath brought me safe thus far, 
and grace will lead me home
    )
)
null

这是我的存储过程非常简单直接

CREATE DEFINER=`root`@`localhost` PROCEDURE `getHymn`(IN `hid` INT)
    READS SQL DATA
BEGIN
    select 
        a.id, a.refrain, b.stanzaId, b.stanzaText 
    from 
        hymns a, hymnstanza b 
    where a.id = hid and a.id = b.hymnid;
END

有人能帮我理解发生了什么吗？

Answer 1

好的，朋友们。我现在发现了这个bug，并且@decez你是绝对正确的，因为有一些额外的echo语句导致在打印数组后出现null。在将近12个小时之后感觉相当轻松，我能够顺利前进。特别感谢@decez。

为了详细说明我做了什么错误，我对fetchAll（）的输出进行了两次JSON化。

fetchAll（）的奇怪行为 - PDO

1 个答案: