# GROUP_CONCAT	

## Syntax

`GROUP_CONCAT(expr)`

## Description

用于返回选中字段字符串连接起来的新字符串

使用逗号连接

## Examples
```
MySQL> select group_concat(`query_id`) from log_statis group by datetime;
+---------------------------------------------------------------------------------------------------------+
| group_concat(`query_id`)                                                                                |
+---------------------------------------------------------------------------------------------------------+
| 445f5875f8854dfa:b9358d5cd86488a2, d5055534e6c04fa0:9b3f645913c4973c, a55801d0764d47fe:a98f3710649dc558 |
+------------------------------------------------------------------------------------------------ --------+
```