php - 从 mysql 表中提取 id

Question

抱歉，这个问题看起来很简单，但我是 php 的新手，我试图让排名出现在索引页面中，但我不知道如何从中的列中提取 id一张 table ，有两张 table :

- raking table -
    city = 'Boston'
    ranking_name = 'the best 5 places'
    business_ids = '67,43,1,6,78'

- business table -
    business_id = '67'
    business_name = 'planet pizza'

如何在前面显示这样的内容:

<ul>
<h2>the best 5 places</h2>
<li><span>1</span><?php echo $business_name ?></li>
<li><span>2</span><?php echo $business_name ?></li>
<li><span>3</span><?php echo $business_name ?></li>
<li><span>4</span><?php echo $business_name ?></li>
<li><span>5</span><?php echo $business_name ?></li>
</ul>

我已经在表中找到了 ID，所以我需要非常相似的东西，任何人都可以帮助我。

感谢所有的帮助问候

Answer 1

尝试使用这个查询

SELECT * FROM business_table WHERE business_id IN ( SELECT business_id FROM ranking_table WHERE city='Boston' );

参见 Demo

你的代码，

$con=mysqli_connect("HOSTNAEM","USERNAME","PASSWORD","DB") die('Could not connect: ' . mysql_error());

$query = "SELECT * FROM business_table WHERE business_id IN ( SELECT business_id FROM ranking_table WHERE city='Boston' )";

while($row = mysqli_fetch_array($query))
{
  echo '<li><span>1</span>'+$row['$business_name']+'></li></br>';
}