bitmap_to_base64
Description
Converts a bitmap to a Base64-encoded string. This function is supported from v2.5.
Syntax
VARCHAR bitmap_to_base64(BITMAP bitmap)
Parameters
bitmap
: the bitmap to convert. This parameter is required. If the input value is invalid, an error is returned.
Return value
Returns a value of the VARCHAR type.
Examples
Example 1: Use this function with other bitmap functions.
select bitmap_to_base64(bitmap_from_string("0, 1, 2, 3"));
+----------------------------------------------------+
| bitmap_to_base64(bitmap_from_string('0, 1, 2, 3')) |
+----------------------------------------------------+
| AjowAAABAAAAAAADABAAAAAAAAEAAgADAA== |
+----------------------------------------------------+
1 row in set (0.00 sec)
select bitmap_to_base64(to_bitmap(1));
+--------------------------------+
| bitmap_to_base64(to_bitmap(1)) |
+--------------------------------+
| AQEAAAA= |
+--------------------------------+
1 row in set (0.00 sec)
select bitmap_to_base64(bitmap_empty());
+----------------------------------+
| bitmap_to_base64(bitmap_empty()) |
+----------------------------------+
| AA== |
+----------------------------------+
1 row in set (0.00 sec)
Example 2: Convert each value in a BITMAP column into Base64-encoded strings.
-
Create an Aggregate table
page_uv
where theAGGREGATE KEY
is (page_id
,visit_date
). This table contains a BITMAP columnvisit_users
whose values are to be aggregated.CREATE TABLE `page_uv`
(`page_id` INT NOT NULL,
`visit_date` datetime NOT NULL,
`visit_users` BITMAP BITMAP_UNION NOT NULL
) ENGINE=OLAP
AGGREGATE KEY(`page_id`, `visit_date`)
DISTRIBUTED BY HASH(`page_id`)
PROPERTIES (
"replication_num" = "3",
"storage_format" = "DEFAULT"
); -
Insert data into this table.
insert into page_uv values
(1, '2020-06-23 01:30:30', to_bitmap(13)),
(1, '2020-06-23 01:30:30', to_bitmap(23)),
(1, '2020-06-23 01:30:30', to_bitmap(33)),
(1, '2020-06-23 02:30:30', to_bitmap(13)),
(2, '2020-06-23 01:30:30', to_bitmap(23));
select * from page_uv order by page_id;
+---------+---------------------+-------------+
| page_id | visit_date | visit_users |
+---------+---------------------+-------------+
| 1 | 2020-06-23 01:30:30 | NULL |
| 1 | 2020-06-23 02:30:30 | NULL |
| 2 | 2020-06-23 01:30:30 | NULL |
+---------+---------------------+-------------+ -
Convert each value in the
visit_users
column into a Base64-encoded string.select page_id, bitmap_to_base64(visit_users) from page_uv;
+---------+------------------------------------------+
| page_id | bitmap_to_base64(visit_users) |
+---------+------------------------------------------+
| 1 | CgMAAAANAAAAAAAAABcAAAAAAAAAIQAAAAAAAAA= |
| 1 | AQ0AAAA= |
| 2 | ARcAAAA= |
+---------+------------------------------------------+