Question

<html>
<head>
    <meta http-equiv = "content-type" content = "text/html; charset = utf-8" />
    <title>Using file functions PHP</title>
</head>
<body>
<h1>Web Development - Lab05</h1>
<?php
   require_once("settings.php");
   $dbconnect = @mysqli_connect($host, $user, $pswd, $dbnm);
    if($dbconnect->connect_errno >0)
    {
        die('Unable to connecto to database [' . $db->connect_error . ']');
    }

    $queryResult = "SELECT car_id, make, model, price FROM cars";

    echo "<table width='100%' border='1'>";
    echo "<tr><th>ID</th><th>Make</th><th>Model</th><th>Price</th></tr>";

    //initiate array 
    $displayrow= mysqli_fetch_array($queryResult);

    //initiate while loop to iterate through table
    while($displayrow)
    {
        echo "<tr>";
        echo "<td>" . $row['ID'] . "</td>";
        echo "<td>" . $row['Make'] . "</td>";
        echo "<td>" . $row['Model'] . "</td>";
        echo "<td>" . $row['Price'] . "</td>";
        echo "</tr>";
    }
    echo "</table>";
    mysqli_close($dbconnect);
?>
</body>
</html>

这是我的头脑，我无法弄清楚为什么除了Table标题之外它不会显示实际数据。无论我用什么。我试过mysqli_fetch_array，mysqli_fetch_row，mysqli_fetch_assoc但没有任何作用。

帮助和解释为什么它不显示数据将非常感激：）

Answer 1

首先：您没有运行查询，只是将查询文本放在变量中。你需要使用mysqli_query。

第二：你应该将mysqli_fetch_array添加到循环中。

例如：

while($displayrow = mysqli_fetch_array($queryResult))
{

}

否则你只会获得第一行。

第三：数组键区分大小写。正如Jeribo指出的那样，没有$row['ID']，在您的查询中引用了$row['car_id']。 $row['Make']与$row['make']不同。

Answer 2

如果你想在外面查询，你仍然需要在循环中设置它：

$result = $db->query($queryResult)

while($row = $result ->fetch_assoc()){
...
}

这里显示了一个好的教程：http://codular.com/php-mysqli

Answer 3

$ row需要初始化，所以为什么不尝试：

while($row = mysqli_fetch_array($queryResult))
{
    ....
}

Answer 4

您必须先获取结果集，然后尝试从结果集

中获取数组

<?php
   require_once("settings.php");
   $dbconnect = @mysqli_connect($host, $user, $pswd, $dbnm);
    if($dbconnect->connect_errno >0)
    {
        die('Unable to connecto to database [' . $db->connect_error . ']');
    }

    $query = "SELECT car_id, make, model, price FROM cars";
    $resultSet=mysqli_query($dbconnect,$query)
    echo "<table width='100%' border='1'>";
    echo "<tr><th>ID</th><th>Make</th><th>Model</th><th>Price</th></tr>";

    //initiate array 
    $displayrow= mysqli_fetch_array( $resultSet);

    //initiate while loop to iterate through table
    while($displayrow)
    {
        echo "<tr>";
        echo "<td>" . $row['ID'] . "</td>";
        echo "<td>" . $row['Make'] . "</td>";
        echo "<td>" . $row['Model'] . "</td>";
        echo "<td>" . $row['Price'] . "</td>";
        echo "</tr>";
    }
    echo "</table>";
    mysqli_close($dbconnect);
?>

http://www.w3schools.com/php/func_mysqli_fetch_array.asp

Answer 5

请精确查询Query中的字段名称（car_id，make，...）

while($displayrow= mysql_fetch_assoc($queryResult) )
{
echo "<tr>";
    echo "<td>" . $displayrow['car_id'] . "</td>";
    echo "<td>" . $displayrow['make'] . "</td>";
    echo "<td>" . $displayrow['model'] . "</td>";
    echo "<td>" . $displayrow['price'] . "</td>";
    echo "</tr>";
}

PHP - SQL选择数据显示

5 个答案: