MySQL选择列的唯一行条目作为新视图或表中的列

Question

I have a dilemma. I am using a CMS that creates a database table where the records are populated as follows:

+------------+----------------+
| field_name |  field_value   |
+------------+----------------+
| your-name  | Adam           |
| your-email | adam@email.com |
| your-name  | Ben            |
| your-email | en@email.com   |
+------------+----------------+

where field_name and field_value are column names. Also, 'your-name' and 'your-email' are are the input names of forms in a webpage.

(there are other columns but none of them have a unique row entry)

My question is, how do i create a table or view so that I can get to this from the above table?

+-----------+----------------+
| your-name |   your-email   |
+-----------+----------------+
| Adam      | Adam@email.com |
| Ben       | Ben@email.com  |
+-----------+----------------+

I have thought about creating views and joining them but I cannot seem to get it working.

Any ideas how to implement this?

Thank you!

Answer 1

Do you have an ID in your table? If you have, you could use this:

SELECT
  MAX(CASE WHEN field_name='your-name' THEN field_value END) your_name,
  MAX(CASE WHEN field_name='your-email' THEN field_value END) your_email
FROM
  yourtable
GROUP BY
  id

Please see fiddle here .

Answer 2

Doesn't your table 1 have kind of an id column like this (so that (id, field_name) is the primary key of this table)?

+----+------------+----------------+
| id | field_name |  field_value   |
+----+------------+----------------+
| 1  | your-name  | Adam           |
| 1  | your-email | adam@email.com |
| 2  | your-name  | Ben            |
| 2  | your-email | en@email.com   |
+----+------------+----------------+

Then you could do...

SELECT DISTINCT myTableAlias.id,
    (SELECT field_value FROM table
     WHERE id=myTableAlias.id AND field_name = 'your-name') your-name,
    (SELECT field_value FROM table
     WHERE id=myTableAlias.id AND field_name = 'your-email') your-email,
FROM table myTableAlias