我正在尝试编写一个 mysql 查询来提取这种格式的数据:
<table>
<caption>table title and/or explanatory text</caption>
<thead>
<tr>
<th>User ID</th>
<th>First Name</th>
<th>Last Name</th>
<th>Field Name 1</th>
<th>Field Name 2</th>
<th>Field Name 3</th>
<th>Field Name 4</th>
<th>Field Name 5</th>
</tr>
</thead>
<tbody>
<?php
while ($row = mysqli_fetch_array($query)) {
echo "<tr>
<td>" .$row{'user_id'}. "</td>
<td>" .$row{'first_name'}. "</td>
<td>" .$row{'last_name'}. "</td>
<td>" .$row{'field_name_1'}. "</td>
<td>" .$row{'field_name_2'}. "</td>
<td>" .$row{'field_name_3'}. "</td>
<td>" .$row{'field_name_4'}. "</td>
<td>" .$row{'field_name_5'}. "</td>
</tr>";
}
?>
</tbody>
</table>
数据库中的表格式如下。
表:用户数据
user_id | first_name | last_name |
------------------------------------------------------
1 | Jeff | Smith |
------------------------------------------------------
2 | Bob | Smith |
------------------------------------------------------
3 | Steve | Smith |
------------------------------------------------------
4 | Mary | Smith |
------------------------------------------------------
5 | Anna | Smith |
------------------------------------------------------
表:自定义字段
custom_field_id | name |
-------------------------------------
3 | field name |
-------------------------------------
5 | field name |
-------------------------------------
7 | field name |
-------------------------------------
9 | field name |
-------------------------------------
11 | field name |
-------------------------------------
表:custom_field_data
user_id | custom_field_id | value |
------------------------------------------------------
1 | 3 | XXXX |
------------------------------------------------------
1 | 5 | BBBB |
------------------------------------------------------
1 | 7 | CCCC |
------------------------------------------------------
1 | 9 | ZZZZ |
------------------------------------------------------
1 | 11 | YYYY |
------------------------------------------------------
2 | 3 | XXXX |
------------------------------------------------------
2 | 5 | BBBB |
------------------------------------------------------
2 | 7 | CCCC |
------------------------------------------------------
2 | 9 | ZZZZ |
------------------------------------------------------
3 | 3 | XXXX |
------------------------------------------------------
3 | 5 | BBBB |
------------------------------------------------------
3 | 9 | ZZZZ |
------------------------------------------------------
3 | 11 | YYYY |
------------------------------------------------------
我正在寻找查询数据然后使用 PHP 或 AJAX 将其打印到屏幕的最佳解决方案。这可能吗？用json会不会更好？ 一个示例查询会很棒。
仅供引用:从长远来看，所有提取的数据都需要在屏幕上进行过滤。感谢您的帮助。
我想要的输出是
user_id | first_name | last_name | custom_field_3 | custom_field_5 | custom_field_7 | custom_field_9 | custom_field_11 |
-------------------------------------------------------------------------------------------------------------------------------------------------------------
1 | Jeff | Smith | XXXX | BBBB | CCCC | ZZZZ | YYYY |
-------------------------------------------------------------------------------------------------------------------------------------------------------------
2 | Bob | Smith | XXXX | BBBB | CCCC | ZZZZ | YYYY |
-------------------------------------------------------------------------------------------------------------------------------------------------------------
3 | Steve | Smith | XXXX | BBBB | CCCC | ZZZZ | YYYY |
-------------------------------------------------------------------------------------------------------------------------------------------------------------
4 | Mary | Smith | XXXX | BBBB | CCCC | ZZZZ | YYYY |
-------------------------------------------------------------------------------------------------------------------------------------------------------------
5 | Anna | Smith | XXXX | BBBB | CCCC | ZZZZ | YYYY |
-------------------------------------------------------------------------------------------------------------------------------------------------------------
最佳答案
您可以使用group_concat 函数，https://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat ，我之前的查询是为每个用户获取一条记录...
如果你有一个 SQLfiddle 我可以测试它但是我没有任何数据可以测试......
select ud.firstname, ud.lastname, group_concat(cf.name)
from user_data as ud
join custom_field_data as cfd
on cfd.user_id = ud.user_id
join custom_fields as cf
on cf.custom_field_id = cfd.custom_field_id
我用类似的设置在 3 个表上测试了它，所以我认为它应该可以工作；名称可能需要调整。
更新:
select ud.firstname, ud.lastname, group_concat(cf.name)
from user_data as ud
join custom_field_data as cfd
on cfd.user_id = ud.user_id
join custom_fields as cf
on cf.custom_field_id = cfd.custom_field_id
group by ud.user_id
关于php - 如何做 MySQL Join 并使用 PHP 获取值，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/31908893/