size (cardinality)

description

Syntax

1. BIGINT size(ARRAY<T> arr)
2. BIGINT cardinality(ARRAY<T> arr)

Returns the size of the array, returns NULL for NULL input.

notice

Only supported in vectorized engine

example

1. mysql> set enable_vectorized_engine=true;

3. mysql> select k1,k2,size(k2) from array_test;
4. +------+-----------+------------+
5. | k1   | k2        | size(`k2`) |
6. +------+-----------+------------+
7. |    1 | [1, 2, 3] |          3 |
8. |    2 | []        |          0 |
9. |    3 | NULL      |       NULL |
10. +------+-----------+------------+

12. mysql> select k1,k2,cardinality(k2) from array_test;
13. +------+-----------+-------------------+
14. | k1   | k2        | cardinality(`k2`) |
15. +------+-----------+-------------------+
16. |    1 | [1, 2, 3] |                 3 |
17. |    2 | []        |                 0 |
18. |    3 | NULL      |              NULL |
19. +------+-----------+-------------------+

keywords

SIZE, CARDINALITY