| --- |
| { |
| "title": "BITMAP_AGG", |
| "language": "en" |
| } |
| --- |
| |
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| |
| ## BITMAP_AGG |
| ### description |
| #### Syntax |
| |
| `BITMAP_AGG(expr)` |
| |
| |
| This aggregating function returns a bitmap that aggregates the values of expr, excluding any null values. |
| The type of expr needs to be TINYINT, SMALLINT, INT, or BIGINT. |
| |
| ### example |
| ``` |
| MySQL > select `n_nationkey`, `n_name`, `n_regionkey` from `nation`; |
| +-------------+----------------+-------------+ |
| | n_nationkey | n_name | n_regionkey | |
| +-------------+----------------+-------------+ |
| | 0 | ALGERIA | 0 | |
| | 1 | ARGENTINA | 1 | |
| | 2 | BRAZIL | 1 | |
| | 3 | CANADA | 1 | |
| | 4 | EGYPT | 4 | |
| | 5 | ETHIOPIA | 0 | |
| | 6 | FRANCE | 3 | |
| | 7 | GERMANY | 3 | |
| | 8 | INDIA | 2 | |
| | 9 | INDONESIA | 2 | |
| | 10 | IRAN | 4 | |
| | 11 | IRAQ | 4 | |
| | 12 | JAPAN | 2 | |
| | 13 | JORDAN | 4 | |
| | 14 | KENYA | 0 | |
| | 15 | MOROCCO | 0 | |
| | 16 | MOZAMBIQUE | 0 | |
| | 17 | PERU | 1 | |
| | 18 | CHINA | 2 | |
| | 19 | ROMANIA | 3 | |
| | 20 | SAUDI ARABIA | 4 | |
| | 21 | VIETNAM | 2 | |
| | 22 | RUSSIA | 3 | |
| | 23 | UNITED KINGDOM | 3 | |
| | 24 | UNITED STATES | 1 | |
| +-------------+----------------+-------------+ |
| |
| MySQL > select n_regionkey, bitmap_to_string(bitmap_agg(n_nationkey)) from nation group by n_regionkey; |
| +-------------+---------------------------------------------+ |
| | n_regionkey | bitmap_to_string(bitmap_agg(`n_nationkey`)) | |
| +-------------+---------------------------------------------+ |
| | 4 | 4,10,11,13,20 | |
| | 2 | 8,9,12,18,21 | |
| | 1 | 1,2,3,17,24 | |
| | 0 | 0,5,14,15,16 | |
| | 3 | 6,7,19,22,23 | |
| +-------------+---------------------------------------------+ |
| |
| MySQL > select bitmap_count(bitmap_agg(n_nationkey)) from nation; |
| +-----------------------------------------+ |
| | bitmap_count(bitmap_agg(`n_nationkey`)) | |
| +-----------------------------------------+ |
| | 25 | |
| +-----------------------------------------+ |
| ``` |
| ### keywords |
| BITMAP_AGG |
