连接 2 个 SQL 表，将行拆分为新列

Question

table1的数据库结构如下：

id | name | total

样本数据如下：

1 | Anna  | 100,00€
2 | Peter | 1000,00€
3 | John  | 10,00€

table2的数据库结构如下：

id | code | value

样本数据如下：

1 | Tax 24%  | 20,00€
1 | Tax 14%  | 2,00€
2 | Tax 24%  | 200,00€
2 | Tax 14%  | 20,00€
2 | Tax 24%  | 2,40€
here might also be sales with 0% and 9% tax

我希望 sql php 语句如何在 html 表中显示结果：

 id | name | Tax with 24% | Tax with 14% | Tax with 9% | total
*
1  | Anna |    20,00€    |    2,00 €    |     0%      |  100€

我如何在 MYSQL PHP HTML 中编写这个？

<?php  $query = $this->db->query("select
  order_id,
  firstname,
  lastname,
  total,
  (select value from `" . DB_PREFIX . "order_total` where title='ALV 24%') as tax24,
  (select value from `" . DB_PREFIX . "order_total` where title='ALV 14%') as tax14,
  (select value from `" . DB_PREFIX . "order_total` where title='ALV 9%') as tax9
from
  `" . DB_PREFIX . "order`");

$products = array();

// Check if there are any rows returned from the query
if ($query->num_rows > 0) {

// Loop through the returned rows for processing
foreach ($query->rows as $result) {
    $products[] = array(
        'order_id' => $result['order_id'],
        'firstname' => $result['firstname'],
        'lastname' => $result['lastname'],
        'tax24' => $result['tax24'],
        'tax14' => $result['tax14'],
        'tax9' => $result['tax9'],
        'total' => $result['total'],
    );
}
} 
foreach ($products as $orders) { ?>
<table class="list">
<tr>
<td><?php print $orders['order_id']; ?></td>
<td><?php print $orders['firstname'] . " " . $orders['lastname']; ?></td>
<td><?php print $orders['tax24']; ?></td>
 <td><?php print $orders['tax14']; ?></td>
     <td><?php print $orders['tax9']; ?></td>
     <td><?php print $orders['total']; ?></td>
</tr>
<?php 
}
?>    
</table>    

Answer 1

棘手部分的伪sql：

select
      id,
      name,
      (select value from table2 where code='Tax 24%' and table2.id=table1.id) as tax24,
      (select value from table2 where code='Tax 14%' and table2.id=table1.id) as tax14,
      (select value from table2 where code='Tax 9%' and table2.id=table1.id) as tax9
from
      table1

当然你必须在php中查询并正确显示。

Answer 2

table2.code 必须包含类似 "24","14","24".. 而不是 "Tax 24%" 的值