element_at

SinceVersion 1.2.0

element_at

description

Syntax

T element_at(ARRAY<T> arr, BIGINT position)

T arr[position]

Returns an element of an array located at the input position. If there is no element at the position, return NULL.

position is 1-based and support negtive number.

notice

Only supported in vectorized engine

example

positive position example:

1. mysql> set enable_vectorized_engine=true;

3. mysql> SELECT id,c_array,element_at(c_array, 5) FROM `array_test`;
4. +------+-----------------+--------------------------+
5. | id   | c_array         | element_at(`c_array`, 5) |
6. +------+-----------------+--------------------------+
7. |    1 | [1, 2, 3, 4, 5] |                        5 |
8. |    2 | [6, 7, 8]       |                     NULL |
9. |    3 | []              |                     NULL |
10. |    4 | NULL            |                     NULL |
11. +------+-----------------+--------------------------+

negtive position example:

1. mysql> set enable_vectorized_engine=true;

3. mysql> SELECT id,c_array,c_array[-2] FROM `array_test`;
4. +------+-----------------+----------------------------------+
5. | id   | c_array         | %element_extract%(`c_array`, -2) |
6. +------+-----------------+----------------------------------+
7. |    1 | [1, 2, 3, 4, 5] |                                4 |
8. |    2 | [6, 7, 8]       |                                7 |
9. |    3 | []              |                             NULL |
10. |    4 | NULL            |                             NULL |
11. +------+-----------------+----------------------------------+

keywords

ELEMENT_AT, SUBSCRIPT