BITMAP_AGG

description

Syntax

BITMAP_AGG(expr)

聚合 expr 的值（不包括任何空值）得到 bitmap。 expr 的类型需要为 TINYINT,SMALLINT,INT 和 BIGINT 类型。

example

1. MySQL > select `n_nationkey`, `n_name`, `n_regionkey` from `nation`;
2. +-------------+----------------+-------------+
3. | n_nationkey | n_name         | n_regionkey |
4. +-------------+----------------+-------------+
5. |           0 | ALGERIA        |           0 |
6. |           1 | ARGENTINA      |           1 |
7. |           2 | BRAZIL         |           1 |
8. |           3 | CANADA         |           1 |
9. |           4 | EGYPT          |           4 |
10. |           5 | ETHIOPIA       |           0 |
11. |           6 | FRANCE         |           3 |
12. |           7 | GERMANY        |           3 |
13. |           8 | INDIA          |           2 |
14. |           9 | INDONESIA      |           2 |
15. |          10 | IRAN           |           4 |
16. |          11 | IRAQ           |           4 |
17. |          12 | JAPAN          |           2 |
18. |          13 | JORDAN         |           4 |
19. |          14 | KENYA          |           0 |
20. |          15 | MOROCCO        |           0 |
21. |          16 | MOZAMBIQUE     |           0 |
22. |          17 | PERU           |           1 |
23. |          18 | CHINA          |           2 |
24. |          19 | ROMANIA        |           3 |
25. |          20 | SAUDI ARABIA   |           4 |
26. |          21 | VIETNAM        |           2 |
27. |          22 | RUSSIA         |           3 |
28. |          23 | UNITED KINGDOM |           3 |
29. |          24 | UNITED STATES  |           1 |
30. +-------------+----------------+-------------+

32. MySQL > select n_regionkey, bitmap_to_string(bitmap_agg(n_nationkey)) from nation group by n_regionkey;
33. +-------------+---------------------------------------------+
34. | n_regionkey | bitmap_to_string(bitmap_agg(`n_nationkey`)) |
35. +-------------+---------------------------------------------+
36. |           4 | 4,10,11,13,20                               |
37. |           2 | 8,9,12,18,21                                |
38. |           1 | 1,2,3,17,24                                 |
39. |           0 | 0,5,14,15,16                                |
40. |           3 | 6,7,19,22,23                                |
41. +-------------+---------------------------------------------+

43. MySQL > select bitmap_count(bitmap_agg(n_nationkey))  from nation;
44. +-----------------------------------------+
45. | bitmap_count(bitmap_agg(`n_nationkey`)) |
46. +-----------------------------------------+
47. |                                      25 |
48. +-----------------------------------------+

keywords

BITMAP_AGG