GROUP BY

描述

Group By用来对一个或者多个字段聚合，以此算出相应的数据，比如最大值、最小值、平均值等。

支持版本

>= Ha3 3.7.0

​

语法格式

select:
    SELECT [ ALL | DISTINCT ]
    { * | projectItem [, projectItem ]* }
    FROM tableExpression
    [ WHERE booleanExpression ]
    [ GROUP BY { groupItem [, groupItem ]* } ]
    [ HAVING booleanExpression ]

内置UDAF函数

目前内置的UDAF如下：

用户可以通过定制UDAF的方式扩展聚合逻辑， 请参考。

示例

1. sum：

SELECT brand, SUM(price) FROM phone WHERE nid < 8 GROUP BY brand

2. min：

SELECT brand, MIN(price) FROM phone WHERE nid < 8 GROUP BY brand

3. max：

SELECT brand, MAX(price) FROM phone WHERE nid < 8 GROUP BY brand

4. count：

SELECT brand, COUNT(*) FROM phone WHERE nid < 8 GROUP BY brand

5. avg：

SELECT brand, AVG(price) FROM phone WHERE nid < 8 GROUP BY brand

6. having子句：

SELECT brand FROM phone GROUP BY brand HAVING COUNT(brand) > 10