问题的简化/通用版本

Question

我正在尝试解决的真正问题是如何从WHMCS数据库获取所有客户端及其所有自定义字段。我以为我可以在phpmyadmin中使用查询，以便最终在csv中获得结果。

数据库方案结构的简短说明： WHMCS，有两个额外的表（tblCustomFields和tblCustomFieldsValues），以方便应用程序用户创建的自定义字段。对于创建的每个新自定义字段，名称及其ID都存储在tblCustomFields中。当客户端配置文件中的自定义字段被填充时，该值将与客户端的id和字段名称的id一起存储在tblCustomFieldsValues的行中。

问题的简化/通用版本

我将尝试描述可能适用于许多类似情况的问题的简化通用版本。

假设

我有三张桌子：

+----------------------------------------------------+
|                     tblClients                     |
+----------------------------------------------------+
| id | company   | standard_field1 | standard_field2 |
+----+-----------+-----------------+-----------------+
| 1  | A company | abc             | yz              |
+----+-----------+-----------------+-----------------+
| 2  | B company | xyz             | foo             |
+----+-----------+-----------------+-----------------+
| 3  | C company | zyx             | bar             |
+----+-----------+-----------------+-----------------+


+--------------------------+
|      tblCustomFields     |
+--------------------------+
| id | fieldname           |
+----+---------------------+
| 1  | Custom Field Name 1 |
+----+---------------------+
| 2  | Custom Field Name 2 |
+----+---------------------+
| 3  | Custom Field Name 3 |
+----+---------------------+

+----------------------------------------------------+
|                tblCustomFieldsValues               |
+----------------------------------------------------+
|      relid      |      fieldid       |    value    |
| (corresponds to |   (corresponds to  |             |
|   a client id)  | a custom field id) |             |
+-----------------+--------------------+-------------+
| 1               | 1                  | any value   |
+-----------------+--------------------+-------------+
| 1               | 2                  | some value  |
+-----------------+--------------------+-------------+
| 1               | 3                  | field value |
+-----------------+--------------------+-------------+
| 2               | 1                  | data        |
+-----------------+--------------------+-------------+
| 2               | 2                  | whatever    |
+-----------------+--------------------+-------------+
| 2               | 3                  | anything    |
+-----------------+--------------------+-------------+
| 3               | 1                  | and so on   |
+-----------------+--------------------+-------------+
| 3               | 2                  | and on      |
+-----------------+--------------------+-------------+

目标

我需要从数据库导出到csv的所有客户端的数据。 重要提示：每个客户只能出现一行。预期结果应与此类似：

+-----------------------------------------------------------------------------+
|       query result, clients with their custom fields as extra columns       |
+-----------------------------------------------------------------------------+
| id |  company  | standard | standard |  Custom   |   Custom   |   Custom    |
|    |           |  field1  |  field2  |   Field   |    Field   |    Field    |
|    |           |          |          |   Name 1  |   Name 2   |    Name 3   |
+----+-----------+----------+----------+-----------+------------+-------------+
| 1  | A company | abc      | yz       | any value | some value | field value |
+----+-----------+----------+----------+-----------+------------+-------------+
| 2  | B company | xyz      | foo      | data      | whatever   | anything    |
+----+-----------+----------+----------+-----------+------------+-------------+
| 3  | C company | zyx      | bar      | and so on | and on     |             |
+----+-----------+----------+----------+-----------+------------+-------------+

想法

我认为解决方案是在phpmyadmin中输入查询，然后轻松地在csv中获取结果。

最后一个问题

使用自定义字段在单独的列中获取所有客户端的mysql查询是什么？有没有更好的方法来实现上述目标？

如果您对如何更改标题或问题的任何部分有任何想法，以便更清楚，请发表评论！

Answer 1

select distinct *
from tblClients tc
join tblCustomFieldsValues tcfv on tcfv.client_id = tc.id
join tblCustomFields tcf on tcfv.custom_field_id = tcf.id

Answer 2

您可以使用Pivot获取预期的输出，但由于Mysql不支持pivot，您必须使用case when子句。 SQL查询如下：静态SQL查询：

Select TB.*, TC.`standard_field1`, TC.`standard_field2`
from tblClients TC
Inner Join(
SELECT TBD.Id, TBD.company,
  Max(CASE WHEN (TBD.fieldname ='Custom Field Name 1') THEN TBD.value ELSE NULL END) AS 'Custom Field Name 1',
  Max(CASE WHEN (TBD.fieldname ='Custom Field Name 2') THEN TBD.value ELSE NULL END) AS 'Custom Field Name 2',
  Max(CASE WHEN (TBD.fieldname ='Custom Field Name 3') THEN TBD.value ELSE NULL END) AS 'Custom Field Name 3'
FROM(
Select TC.Id, TC.Company,
  TCF.fieldname, TCFV.Value
  from tblCustomFieldsValues TCFV
  Inner Join tblClients TC
  ON TCFV.relid = TC.ID
  Inner Join tblCustomFields TCF
  ON TCFV.fieldid = TCF.Id) TBD

 Group BY TBD.Id, TBD.company) TB
 On TB.Id = TC.Id

我还提供了SQL fiddle链接，可以帮助您获得完整的数据和输出。

动态SQl查询：

SET @sql = NULL;
SELECT 
  GROUP_CONCAT(DISTINCT
               CONCAT('Max(CASE WHEN (TBD.fieldname =''', UN.fieldname,
                      ''') THEN TBD.value ELSE NULL END) AS ''',UN.fieldname,''''))
    INTO @sql
    FROM (
      Select * from tblCustomFields) UN;

SET @sql =  CONCAT('Select TB.*, TC.`standard_field1`, TC.`standard_field2`
                    from tblClients TC
                    Inner Join(SELECT TBD.Id, TBD.company, ', @sql, ' 
                      FROM(
                        Select TC.Id, TC.Company,
                          TCF.fieldname, TCFV.Value
                          from tblCustomFieldsValues TCFV
                          Inner Join tblClients TC
                          ON TCFV.relid = TC.ID
                          Inner Join tblCustomFields TCF
                          ON TCFV.fieldid = TCF.Id) TBD

                         Group BY TBD.Id, TBD.company) TB On TB.Id = TC.Id');

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

SQL Fiddle链接

我希望这会对你有所帮助。

Mysql查询将表的行作为另一个表的列，使用第三个表中的列名

问题的简化/通用版本

假设

目标

想法

最后一个问题

2 个答案: