PHP-PDO提取循环

问题描述

我想我在这里迷失了方向.

I think I'm losing my mind here.

这是代码. (这是我为了说明这一点而实际要做的工作的简化版本.)

This is the code. (It's a simplified version of what I am actually trying to do in order to demonstrate the point.)

$STH = $DBH->query("SELECT * FROM help");
$STH->setFetchMode(PDO::FETCH_ASSOC);

while($row = $STH->fetch()) {
    echo $row['text'];
    $help_text = $row['text'];
}
echo "->";
echo $help_text;
echo "<-";

使用句柄DBH到MySQL数据库的数据库连接很好(未列出).该查询工作正常.循环内$row['text']的回声可以正常工作多次.但是，在->和<-之间的$help_text回声不起作用，导致显示-><-.我希望回显显示$row['text']的最后一个实例.

The db connection to the MySQL db using the handle DBH is fine (not listed). The query works fine. The echo of $row['text'] within the loop works fine multiple times. However, the echo of $help_text between -> and <- does nothing, resulting in -><- being displayed. I would expect the echo to show the last instance of $row['text'].

请问为什么这不起作用?！

Why is this not working, please?!

推荐答案

您需要在循环外声明它

$help_text = "";
while($row = $STH->fetch()) {
    echo $row['text'];
    $help_text .= $row['text'];
}
echo "->";
echo $help_text;
echo "<-";

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