检索所有行但第一条记录丢失-php问题

Retrieve all row but the first record is missing(检索所有行但第一条记录丢失)

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问题描述

$query = "SELECT * FROM abc";如果 ($result = $db->query($query)) {$row = $result->fetch_assoc();while ($row = $result->fetch_assoc()) {$data[] = array("a"=>$row["a"],"b"=>$row["b"],"c"=>$row["c"],"d"=>$row["d"]);}$result->close();}$db->close();<?php foreach ($data as $row) { ?><form action=""><div class="col-lg-3"><input type="text" value="<?php echo $row['a'] ?>"/><div class="col-lg-3"><input type="text" value="<?php echo $row['b'] ?>"/>
<div class="col-lg-3"><input type="text" value="<?php echo $row['c'] ?>"/>
<div class="col-lg-3"><input type="text" value="<?php echo $row['d'] ?>"/>

</表单><?php } ?>

上面是我用来检索表中所有行的确切代码.奇怪的是我有 5 行，它只显示 4.第一行丢失了.我想知道为什么.

解决方案

在你的代码中，你在开始你的 $row = $result->fetch_assoc();>while 循环.这条线是消耗"的您的第一个原始数据，当您进入循环时，您通过第二次调用相同的方法将光标移动到第二行.

while 循环的条件在内容之前执行，在这里您将找到有关 PHP While 循环

要修复您的代码，请删除第一行.

$query = "SELECT * FROM abc";

    if ($result = $db->query($query)) {

      $row = $result->fetch_assoc();


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

            $data[] = array("a"=>$row["a"], 
                            "b"=>$row["b"],
                            "c"=>$row["c"],
                            "d"=>$row["d"]
                            ); 


        }

        $result->close();
    }

$db->close();

        <?php foreach ($data as $row) { ?>

                <form action="">
                    <div class="col-lg-3">
                        <input type="text" value="<?php echo $row['a'] ?>"/>
                    </div>
                    <div class="col-lg-3">
                        <input type="text" value="<?php echo $row['b'] ?>"/>
                    </div>
                    <div class="col-lg-3">
                        <input type="text" value="<?php echo $row['c'] ?>"/>
                    </div>
                    <div class="col-lg-3">
                        <input type="text" value="<?php echo $row['d'] ?>"/>
                    </div>
                </form>

              <?php } ?>

Above is the exact code that I used to retrieve all the row in a table. The strange part is that I have 5 row and it only show 4. The first row is missing. I wonder why.

解决方案

In your code, you're calling $row = $result->fetch_assoc(); just before starting your while loop. This line is "consuming" your first raw and when you're entering in the loop, you move the cursor to the second row by calling this same method a second time.

The condition of the while loop is executed BEFORE the content, here you'll find more info about PHP While loop

To fix your code, remove this first line.

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