UNION
更新时间：2025-10-16
描述
将多个聚合中间结果聚合为一个。 结果的类型为 agg_state，函数签名与入参一致。
语法
AGGREGATE_FUNCTION_UNION(agg_state)
举例
Plain Text
1mysql [test]>select avg_merge(t) from (select avg_union(avg_state(1)) as t from d_table group by k1)p;
2+----------------+
3| avg_merge(`t`) |
4+----------------+
5| 1 |
6+----------------+keywords
AGG_STATE, UNION