PHP fetchAll(PDO::FETCH_ASSOC) returns 语句中为空

Question

我正在尝试使用 PDO::FETCH_ASSOC.

获取插入到我的数据库中的数据

出于某种原因（可能是缺乏理解...）我无法回显来自 class 方法的数据。

这是 db table 结构：

我想将数据作为$fieldName['value'] => $fieldVal['value']

的关联数组来执行

我有一个 class，通过匹配 tz 和 year 值，select 来自 table 的所有数据。从函数内的 print _r 我收到了一个好的数据。如果我从 class 文件外部调用该方法，我会将所有值接收为 null。

这是我的 class 代码：

function dataExist($tz, $year){
    $tz = 303748891;
    $year = 2017;
    $query = "SELECT * FROM ". $this->table_name ." WHERE tz = ? AND year = ?";

    $stmt = $this->conn->prepare($query);

    $stmt->bindParam(1, $tz);
    $stmt->bindParam(2, $year);

    // execute query
    $stmt->execute();

    //get all data
    $result = $stmt->fetchAll(PDO::FETCH_ASSOC);


    echo '<pre>';
    print_r( $result);
    echo '</pre>';

    return $result;


}

这是我在 class print_r.

方面收到的好结果

Array
(
    [0] => Array
        (
            [id] => 45
            [tz] => 303748891
            [fieldName] => tel
            [fieldVal] => 0547
            [year] => 2017
        )

    [1] => Array
        (
            [id] => 77
            [tz] => 303748891
            [fieldName] => fname
            [fieldVal] => Jon
            [year] => 2017
        )

    [2] => Array
        (
            [id] => 78
            [tz] => 303748891
            [fieldName] => lname
            [fieldVal] => black
            [year] => 2017
        )

    [3] => Array
        (
            [id] => 79
            [tz] => 303748891
            [fieldName] => tel
            [fieldVal] => 5555-555-55
            [year] => 2017
        )

    [4] => Array
        (
            [id] => 80
            [tz] => 303748891
            [fieldName] => mail
            [fieldVal] => aaa@aaa.aaa
            [year] => 2017
        )

    [5] => Array
        (
            [id] => 81
            [tz] => 303748891
            [fieldName] => fname
            [fieldVal] => James
            [year] => 2017
        )

    [6] => Array
        (
            [id] => 82
            [tz] => 303748891
            [fieldName] => lname
            [fieldVal] => White
            [year] => 2017
        )

    [7] => Array
        (
            [id] => 83
            [tz] => 303748891
            [fieldName] => tel
            [fieldVal] => 6669-666-666
            [year] => 2017
        )

    [8] => Array
        (
            [id] => 84
            [tz] => 303748891
            [fieldName] => mail
            [fieldVal] => bbb@bbb.bbb
            [year] => 2017
        )

)

这是来自其他文件的调用：

$dataExist = new Form($db);
$dataExist->dataExist($tz,$year);
echo '<pre>';
print_r( $dataExist);
echo '</pre>';

我收到这个：

Form Object
(
    [conn:Form:private] => PDO Object
        (
        )

    [table_name:Form:private] => submisions
    [id] => 
    [tz] => 
    [fieldName] => 
    [fieldVal] => 
    [year] => 
)

Answer 1

您没有将方法调用的结果分配给变量。变化

$dataExist->dataExist($tz,$year);

到

$thedata = $dataExist->dataExist($tz,$year);

然后

print_r($thedata);

你会看到你所期望的。

PHP fetchAll(PDO::FETCH_ASSOC) returns 语句中为空

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