## `having`
此方法用于配合group方法完成從分組的結果中篩選（通常是聚合條件）數據
## 示例：
~~~
db.name('user').field('userid, username, max(score)').group('userid').having('count(addtime)>3').select()
~~~
- 連接數據庫
- 鏈式操作方法
- distinct
- field
- withoutField
- name
- alias
- force
- join
- leftJoin
- rightJoin
- union
- unionAll
- where
- whereOr
- whereTime
- whereBetweenTime
- whereNotBetweenTime
- whereBetweenTimeField
- whereNotBetweenTimeField
- whereYear
- whereMonth
- whereWeek
- whereDay
- group
- having
- order
- orderRand
- limit
- page
- lock
- comment
- ignore
- inc
- dec
- fetchSql
- 查詢數據
- 聚合查詢
- 新增數據
- 更新數據
- 刪除數據
- 原生操作