GROUP_CONCAT

Description

The GROUP_CONCAT function concatenates multiple rows of results in the result set into a string.

Syntax

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

Parameters

Parameters	Description
<str>	Required. The expression of the value to be concatenated.
<sep>	Optional. The separator between strings.
<col_name>	Optional. The column used for sorting.
<expr>	Optional. The expression used for sorting.

Return Value

Returns a value of type VARCHAR.

Example

select value from test;

+-------+
| value |
+-------+
| a     |
| b     |
| c     |
| c     |
+-------+

select GROUP_CONCAT(value) from test;

+-----------------------+
| GROUP_CONCAT(`value`) |
+-----------------------+
| a, b, c, c            |
+-----------------------+

select GROUP_CONCAT(DISTINCT value) from test;

+-----------------------+
| GROUP_CONCAT(`value`) |
+-----------------------+
| a, b, c               |
+-----------------------+

select GROUP_CONCAT(value, " ") from test;

+----------------------------+
| GROUP_CONCAT(`value`, ' ') |
+----------------------------+
| a b c c                    |
+----------------------------+

select GROUP_CONCAT(value, NULL) from test;

+----------------------------+
| GROUP_CONCAT(`value`, NULL)|
+----------------------------+
| NULL                       |
+----------------------------+