GROUP_CONCAT

GROUP_CONCAT

description

Syntax

VARCHAR GROUP_CONCAT([DISTINCT] VARCHAR str[, VARCHAR sep]) [ORDER BY { col_name | expr} [ASC | DESC])

This function is an aggregation function similar to sum (), and group_concat links multiple rows of results in the result set to a string. The second parameter, sep, is a connection symbol between strings, which can be omitted. This function usually needs to be used with group by statements.

Support Order By for sorting multi-row results, sorting and aggregation columns can be different.

caution

group_concat don't support using distinct with order by together.

example

mysql> select value from test;
+-------+
| value |
+-------+
| a     |
| b     |
| c     |
| c     |
+-------+

mysql> select GROUP_CONCAT(value) from test;
+-----------------------+
| GROUP_CONCAT(`value`) |
+-----------------------+
| a, b, c, c              |
+-----------------------+

mysql> select GROUP_CONCAT(value, " ") from test;
+----------------------------+
| GROUP_CONCAT(`value`, ' ') |
+----------------------------+
| a b c c                     |
+----------------------------+

mysql> select GROUP_CONCAT(DISTINCT value) from test;
+-----------------------+
| GROUP_CONCAT(`value`) |
+-----------------------+
| a, b, c               |
+-----------------------+

mysql> select GROUP_CONCAT(value, NULL) from test;
+----------------------------+
| GROUP_CONCAT(`value`, NULL)|
+----------------------------+
| NULL                       |
+----------------------------+

SELECT abs(k3), group_concat(distinct cast(abs(k2) as varchar) order by abs(k1), k5) FROM bigtable group by abs(k3) order by abs(k3);     +------------+-------------------------------------------------------------------------------+
| abs(`k3`)  | group_concat(DISTINCT CAST(abs(`k2`) AS CHARACTER), ORDER BY abs(`k1`), `k5`) |
+------------+-------------------------------------------------------------------------------+
|        103 | 255                                                                           |
|       1001 | 1989, 1986                                                                    |
|       1002 | 1989, 32767                                                                   |
|       3021 | 1991, 32767, 1992                                                             |
|       5014 | 1985, 1991                                                                    |
|      25699 | 1989                                                                          |
| 2147483647 | 255, 1991, 32767, 32767                                                       |
+------------+-------------------------------------------------------------------------------+

### keywords
GROUP_CONCAT,GROUP,CONCAT