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BITMAP_UNION

Description

Calculates the union of input Bitmaps and returns a new Bitmap.

Syntax

BITMAP_UNION(<expr>)

Arguments

ArgumentDescription
<expr>Data type supporting Bitmap

Return Value

Returns a value of Bitmap type. If there is no valid data in the group, returns an empty Bitmap.

Example

-- setup
CREATE TABLE pv_bitmap (
dt INT,
page INT,
user_id BITMAP
) DISTRIBUTED BY HASH(dt) BUCKETS 1
PROPERTIES ("replication_num" = "1");
INSERT INTO pv_bitmap VALUES
(1, 100, to_bitmap(100)),
(1, 100, to_bitmap(200)),
(1, 100, to_bitmap(300)),
(2, 200, to_bitmap(300));
select bitmap_to_string(bitmap_union(user_id)) from pv_bitmap;
+-----------------------------------------+
| bitmap_to_string(bitmap_union(user_id)) |
+-----------------------------------------+
| 100,200,300 |
+-----------------------------------------+
select bitmap_to_string(bitmap_union(user_id)) from pv_bitmap where user_id is null;
+-----------------------------------------+
| bitmap_to_string(bitmap_union(user_id)) |
+-----------------------------------------+
| |
+-----------------------------------------+