如何通过SELECT查询获取并展示指定UID的所有行数据？

Hey there! Let's get your code working to show all UID=1 records in an HTML table. Right now, two main issues are causing only one row to display—let's break them down and fix them step by step:

1. Variable Name Mismatch #

In your code, you store the user ID in $uid (from $_SESSION['login']), but try to bind $Uid (uppercase U) to the prepared statement. PHP is case-sensitive, so this will fail to bind the correct value. We need to fix that variable name to match.

2. Single Fetch Call #

You only call $result2->fetch_assoc() once, which only grabs the first row of your result set. To get all rows, you need to loop through the result set with a while loop—this will keep fetching rows until there are no more left.

Corrected Full Code #

Here's the updated code that fixes both issues and outputs the results in an HTML table:

<?php
// Make sure session is started before accessing $_SESSION
session_start();
$uid = $_SESSION['login'];

// Adjusted ORDER BY to sort by day/time (more meaningful than UID for single user)
$sql2 = "SELECT * FROM Activities WHERE uid=? ORDER BY day, time LIMIT 6";
$stmt2 = $connection->prepare($sql2);
// Bind the correct variable ($uid, not $Uid)
$stmt2->bind_param('i', $uid);
$stmt2->execute();
$result2 = $stmt2->get_result();
?>

<!-- HTML Table for Displaying Results -->
<table border="1" cellpadding="8" cellspacing="0">
    <thead>
        <tr>
            <th>UID</th>
            <th>Day</th>
            <th>Activity</th>
            <th>Time</th>
            <th>Remarks</th>
        </tr>
    </thead>
    <tbody>
        <?php
        // Loop through every row in the result set
        while ($row2 = $result2->fetch_assoc()) {
        ?>
        <tr>
            <td><?php echo htmlspecialchars($row2['Uid']); ?></td>
            <td><?php echo htmlspecialchars($row2['day']); ?></td>
            <td><?php echo htmlspecialchars($row2['activity']); ?></td>
            <td><?php echo htmlspecialchars($row2['time']); ?></td>
            <td><?php echo htmlspecialchars($row2['remarks']); ?></td>
        </tr>
        <?php
        }
        // Handle case where no results are found
        if ($result2->num_rows === 0) {
        ?>
        <tr>
            <td colspan="5">No activities found for this user.</td>
        </tr>
        <?php
        }
        ?>
    </tbody>
</table>

<?php
// Clean up database resources
$stmt2->close();
?>

Key Improvements Explained: #

• session_start(): Added at the top (critical to access $_SESSION before any output is sent to the browser).
• Fixed variable binding: Matched $uid across the code to ensure the correct user ID is passed to the query.
• Meaningful sorting: Changed ORDER BY Uid to ORDER BY day, time—since you're filtering for a single UID, sorting by date/time makes results easier to read.
• while loop: Iterates over every row returned, so all 4 (or up to 6) records will display.
• htmlspecialchars(): Escapes special characters to prevent XSS attacks—always a safe practice when displaying user-generated data.
• No-results fallback: Shows a friendly message if there are no activities for the user.

内容的提问来源于stack exchange，提问作者Dellyz