# GROUP BY
完整的分析语句语法如下：
```
SELECT [DISTINCT] (* | expression) [AS alias] [, ...]
[GROUP BY expression [, ...] [HAVING predicates]]
[ORDER BY expression [ASC | DESC] [, ...]]
[LIMIT size OFFSET offset]
```
其中，GROUP BY表示按值分组。本章节内容将介绍GROUP BY语法参数说明及示例。
#### 按字段的值分组
```
*|SELECT age GROUP BY age
```
表1按字段的值分组 
| age |
|:---|
| 28  |
| 32  |
| 36  |
   
#### 按字段别名分组
```
*|SELECT account_number AS num GROUP BY num
```
表2按字段别名分组 
| num |
|:---|
| 1   |
| 16  |
| 13  |
| 18  |
   
#### 按多个字段分组
示例1：按多个字段分组，查看不同年龄人数分布。
```
*|SELECT account_number AS num, age GROUP BY num, age
```
表3按多个字段分组 
| num | age |
|:---|:---|
| 1   | 32  |
| 16  | 36  |
| 13  | 28  |
| 18  | 32  |
   
示例2：查看主机hcss_ecs_3924的region分布，按多个字段分组。
```
hostName = ‘hcss_ecs_3924’|SELECT hostName AS name, region GROUP BY name, region
```
表4按多个字段分组结果示例 
| name          | region     |
|:---|:---|
| hcss_ecs_3924 | cn-north-7 |
   
#### 使用SQL函数
函数相关内容请参见[函数](https://support.huaweicloud.com/usermanual-secmaster/secmaster_01_0121.html#secmaster_01_0121)。
```
*|SELECT LENGTH(lastname) AS len, COUNT(*) AS count GROUP BY LENGTH(lastname)
```
表5使用SQL函数 
| len | count |
|:---|:---|
| 4   | 2     |
| 5   | 2     |