如何在行和列反转时显示数据库中的数据

Question

I have to deal with a table like this one with approximately a couple of hundreds of #id (and counting).

id     field_name     field_value  
1      name           pasta  
1      lat            41.27651  
1      long           11.45234  
2      name           pizza  
2      lat            43.53455 
2      long           12.62346
..     ....           ........
..     ....           ........
..     ....           ........

I need to build an XML file that allows me to add markers on Google Map with a structure like this:

<makers>
    <marker name="$name" lat="$lat" long="$long" />
    <marker name="$name" lat="$lat" long="$long" />
    (...)
</markers>

I am trying to do a query like this and then put all the info in arrays and play with some foreach but I am failing so hard that I can't go on.

$query = "  SELECT field_val
        FROM table
        WHERE field_name='Name'";

The main problem is that i am not able to work with a structure like this, given the fact that a probably better structure would have been like this

id    name    lat       long
1     pasta   41.27651  11.45234
2     pizza   43.53455  12.62346
..    ...     ...       ...

Please note that i can't change the way the entries go in the DB and that the structure of the table is more complicated than the one showed here (with approx. 15 field_name per id, not all of them necessary).

Sorry for the poor english and thanks for your time.

Answer 1

SELECT 
  id,
  GROUP_CONCAT(if(fieldname='name', field_value, NULL)) AS 'name', 
  GROUP_CONCAT(if(fieldname='lat', field_value, NULL)) AS 'lat', 
  GROUP_CONCAT(if(fieldname='long', field_value, NULL)) AS 'long' 
FROM table 
GROUP BY id;