Question

我有一系列鏈接將信息傳遞到新頁面以運行MySQL查詢。這是從源代碼的鏈接之一：

<a class="bloglink" href="parknews.php?tpf_news.park_id=5"> 

，這是生成的鏈接代碼：

$park_id = $_GET['tpf_news.park_id']; 
$sql = 'SELECT headline, story, DATE_FORMAT(date, "%d-%M-%Y") AS date, name 
FROM tpf_news 
INNER JOIN tpf_parks ON tpf_news.park_id = tpf_parks.park_id WHERE tpf_news.park_id = $park_id ORDER BY date DESC' ; 

：

<a class="bloglink" href="parknews.php?tpf_news.park_id=<?php echo $row2['park_id'];?>"> 
<?php echo $row2['name']; ?> 
</a> 

使用該信息在這裏查詢這導致此錯誤顯示：

Error fetching news: SQLSTATE[42S22]: Column not found: 1054 Unknown column '$park_id' in 'where clause' 

我不知道爲什麼它不起作用。如果在查詢中我將WHERE tpf_news.park_id = $park_id替換爲WHERE tpf_news.park_id = 6（或任何其他數字），它工作正常。

任何想法？

Answer 1

當你的字符串在引號中時，你的變量不會被內插。因此，你需要用雙引號代替：

$sql = "SELECT headline, story, DATE_FORMAT(date, '%d-%M-%Y') AS date, name 
FROM tpf_news 
INNER JOIN tpf_parks ON tpf_news.park_id = tpf_parks.park_id WHERE tpf_news.park_id = $park_id ORDER BY date DESC" ; 

或者使用串聯：

$sql = 'SELECT headline, story, DATE_FORMAT(date, "%d-%M-%Y") AS date, name 
FROM tpf_news 
INNER JOIN tpf_parks ON tpf_news.park_id = tpf_parks.park_id WHERE tpf_news.park_id =' . $park_id .' ORDER BY date DESC' ; 

僅供參考，您也大開SQL injections

Answer 2

你有你的SQL單引號。這意味着變量不會按照您的想法顯示。使用雙引號。

爲了上帝的愛我們準備了陳述。

$sql = "SELECT headline, story, DATE_FORMAT(date, "%d-%M-%Y") AS date, name 
FROM tpf_news 
INNER JOIN tpf_parks ON tpf_news.park_id = tpf_parks.park_id WHERE tpf_news.park_id=$park_id ORDER BY date DESC" ; 

$sql = 'SELECT headline, story, DATE_FORMAT(date, "%d-%M-%Y") AS date, name 
FROM tpf_news 
INNER JOIN tpf_parks ON tpf_news.park_id = tpf_parks.park_id WHERE tpf_news.park_id='.$park_id.' ORDER BY date DESC' ;