GROUP_CONCAT ORDER BY

Question

I've a table like:

+-----------+-------+------------+
| client_id | views | percentage |
+-----------+-------+------------+
|         1 |     6 |         20 |
|         1 |     4 |         55 |
|         1 |     9 |         56 |
|         1 |     2 |         67 |
|         1 |     7 |         80 |
|         1 |     5 |         66 |
|         1 |     3 |         33 |
|         1 |     8 |         34 |
|         1 |     1 |         52 |

I tried group_concat:

SELECT li.client_id, group_concat(li.views) AS views,  
group_concat(li.percentage) FROM li GROUP BY client_id;

+-----------+-------------------+-----------------------------+
| client_id | views             | group_concat(li.percentage) |
+-----------+-------------------+-----------------------------+
|         1 | 6,4,9,2,7,5,3,8,1 | 20,55,56,67,80,66,33,34,52  |
+-----------+-------------------+-----------------------------+

But I want to get the views in order, like:

+-----------+-------------------+----------------------------+
| client_id | views             | percentage                 |
+-----------+-------------------+----------------------------+
|         1 | 1,2,3,4,5,6,7,8,9 | 52,67,33,55,66,20,80,34,56 |
+-----------+-------------------+----------------------------+

Answer 1

Try

SELECT li.clientid, group_concat(li.views ORDER BY li.views) AS views, group_concat(li.percentage ORDER BY li.percentage) FROM table_views li GROUP BY client_id

http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function%5Fgroup-concat

Answer 2

The group_concat supports its own order by clause

http://mahmudahsan.wordpress.com/2008/08/27/mysql-the-group_concat-function/

So you should be able to write:

SELECT li.clientid, group_concat(li.views order by views) AS views,
group_concat(li.percentage order by percentage) 
FROM table_views GROUP BY client_id

Answer 3

In IMPALA, not having order in the GROUP_CONCAT can be problematic, over at Coders'Co. we have some sort of a workaround for that (we need it for Rax/Impala). If you need the GROUP_CONCAT result with an ORDER BY clause in IMPALA, take a look at this blog post: http://raxdb.com/blog/sorting-by-regex/

Answer 4

You can use ORDER BY inside the GROUP_CONCAT function in this way:

SELECT li.client_id, group_concat(li.percentage ORDER BY li.views ASC) AS views, 
group_concat(li.percentage ORDER BY li.percentage ASC) 
FROM li GROUP BY client_id