Mysql How to concat on field of all result rows

Question

Is it possible to concat (in one field), all rows from result.
My table is like that :

ID    STRING
1      a,aa
2      xxx
3      str
4      aa,xx

And I want somthing like:

ID    STRING    CONCAT
1      a,aa     a,aa xxx str aa,xx
2      xxx      a,aa xxx str aa,xx
3      str      a,aa xxx str aa,xx
4      aa,xx    a,aa xxx str aa,xx

I tried with GROUP_CONCAT, but that doesn't do what I want ..

Any idea ? Bye

UPDATE 2:
Actually, here is my request

SELECT DISTINCT 
(SELECT GROUP_CONCAT(LABEL_ID) FROM DOCUMENT WHERE ENTITY_ID = `p`.id) as label,
`p`.*,
(6371*acos(cos(radians(48.8817))*cos(radians(LATITUDE))*cos(radians(LONGITUDE) - radians(2.3822))+sin(radians(48.8817))*sin(radians(LATITUDE)))) AS `dist`, 
`a`.`NUMBER_COMM`, 
`a`.`AVE` 
FROM `PRO` AS `p` 
INNER JOIN `PRO_JOB_RELATION` AS `j_rel` ON p.ID = j.ID_PRO 
INNER JOIN `COMM` AS `a` ON p.ID = a.ID_PRO WHERE (p.ETAT = 1) 
AND (j.ID_METIER = '15') 
HAVING (dist <= 300 and dist <= `p`.RAYON) 
ORDER BY ((AVE * 4) + ((5 * NUMBER_COMM ) / 100)) - ((( 5 * dist) / 100) * 20) / 3 DESC,  `CHECKED` DESC

And I got this result :

ID    LABEL    OTHER
1      2,3      ...
2     NULL      ...
3      2        ...
4      8,2      ...

And what I really need is something like that :

ID    LABEL    OTHER  LABEL_CONCAT
1      2,3      ...      2,3,8
2     NULL      ...      2,3,8
3      2        ...      2,3,8
4      8,2      ...      2,3,8

And I can't do that ... Can you help me ?

Answer 1

You can use group_concat, but in a subquery

select id, string, (select group_concat(string SEPARATOR ' ') 
                    from Table1)
from Table1

see SqlFiddle

Answer 2

Yes. It is possible. And you can do it using the GROUP_CONCAT aggregate function.

But the result you specified would require either a subquery in the SELECT list, or a JOIN to an inline view, eg

SELECT t.id      AS `ID
     , t.string  AS `STRING`
     , c.gc      AS `CONCAT`
  FROM mytable t
 CROSS 
  JOIN ( SELECT GROUP_CONCAT(s.string ORDER BY s.id) AS `gc`
          FROM mytable s
       ) c 
 ORDER BY t.id

Note that the return from GROUP_CONCAT is limited, by some system variables, max_group_concat_len (?something like that) and max_allowed_packet .