Question

上半部分正常工作。 $selectedVerb和$verbNum都会恢复正常并显示出来。当我尝试在下一个查询中使用$verbNum时，它会导致错误：

致命错误：未捕获错误：调用成员函数fetch_array（） on boolean;堆栈跟踪：＃0 {main}抛出。

代码：

if ($stmt = $dbc->prepare("SELECT verbNum FROM verblist WHERE mainVerb = ? ")){

    $stmt->bind_param("s", $selectedVerb);

    $stmt->execute();

    $stmt->bind_result($verbNum);

    $stmt->fetch();

    echo '<span>'.$selectedVerb.' is part of verb number: '.$verbNum. '</span>';

    settype($verbNum, "integer");

    $verbListarray = mysqli_query($dbc, "SELECT mainVerb FROM verblist WHERE verbNum = $verbNum");

    while($row = $verbListarray->fetch_array())
    {
        echo $row['mainVerb'];
        echo "<br />";
    }    

    $stmt->close();
}

Answer 1

以程序方式混合OOP方式不是一个好方法，所以如下所示： -

if ($stmt = $dbc->prepare("SELECT verbNum FROM verblist WHERE mainVerb = ? ")){

    $stmt->bind_param("s", $selectedVerb);

    $stmt->execute();

    $stmt->bind_result($verbNum);

    $stmt->fetch();

    echo '<span>'.$selectedVerb.' is part of verb number: '.$verbNum. '</span>';

    //settype($verbNum, "integer");

    $stmt->close();

    $stmt = $dbc->prepare("SELECT mainVerb FROM verblist WHERE verbNum = ?");

    $stmt->bind_param("i", $verbNum);

    $stmt->execute();

     while($row = $stmt->fetch()){
        echo $row['mainVerb'];
        echo "<br />";
      }    

    $stmt->close();
}

Answer 2

没有充分理由在循环中执行多个查询，只需加入两个查询。

$stmt = $dbc->prepare("
    SELECT t1.verbNum, t2.mainVerb
    FROM verblist AS t1
    JOIN verblist AS t2 ON t1.verbNum = t2.verbNum
    WHERE t1.mainVerb = ?
    ORDER BY t1.verbNum")
$stmt->bind_param("s", $selectedVerb);
$stmt->execute();
$stmt->bind_result($verbNum, $mainVerb);
$firstRow = true;
while ($stmt->fetch()) {
    if ($firstRow) {
        echo '<span>'.$selectedVerb.' is part of verb number: '.$verbNum. '</span>';
        $firstRow = false;
    }
    echo $mainVerb . "<br>";
}

myslqi查询在准备好的语句后继续返回布尔值

2 个答案: