数据仓库服务 GAUSSDB(DWS)-Roaring Bitmap聚合函数:rb_or_cardinality_agg(roaringbitmap)

时间：2023-12-15 11:45:23

rb_or_cardinality_agg(roaringbitmap)

描述：将分组内的roaringbitmap按照并集计算后的基数。

示例：

SELECT a, rb_or_cardinality_agg(b) FROM r1 GROUP BY a ORDER BY 1;
 a  | rb_or_cardinality_agg
----+-----------------------
 1  |                     1
 2  |                     2
 3  |                     2
 4  |                     2
 5  |                     2
 6  |                     2
 7  |                     2
 8  |                     2
 9  |                     2
 10 |                     2
(10 rows)