bitmap_union_count

Description

Computes the union of input Bitmaps and returns their cardinality.

Syntax

BITMAP_UNION_COUNT(<expr>)

Parameters

Parameter	Description
<expr>	Supported data types of BITMAP

Return Value

Returns the size of the Bitmap union, that is, the number of elements after deduplication

Example

select dt,page,bitmap_to_string(user_id) from pv_bitmap;

+------+------+---------------------------+
| dt   | page | bitmap_to_string(user_id) |
+------+------+---------------------------+
|    1 | 100  | 100,200,300               |
|    2 | 200  | 300                       |
+------+------+---------------------------+

Calculate the deduplication value of user_id:

select bitmap_union_count(user_id) from pv_bitmap;

+-------------------------------------+
| bitmap_count(bitmap_union(user_id)) |
+-------------------------------------+
|                                   3 |
+-------------------------------------+