# HAVING
HAVING与聚合函数和GROUP BY一起使用，来控制选择哪些组。
HAVING能够在分组和聚合计算之后，过滤掉不满足给定条件的组。
例如：
```
SELECT count(*), mktsegment, nationkey,
CAST(sum(acctbal) AS bigint) AS totalbal
FROM customer
GROUP BY mktsegment, nationkey
HAVING sum(acctbal) > 5700000
ORDER BY totalbal DESC;
```