element_at

element_at

Description

Syntax:

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

T arr[position]

This function returns the element of the specified positioin in the array. If there is no element at the position, it will return NULL.

position is 1-based and support negtive number.

Note:

It is only supported in vectorized engine.

Example

Positive position example:

mysql> set enable_vectorized_engine=true;

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

Negtive position example:

mysql> set enable_vectorized_engine=true;

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

Keywords

ELEMENT_AT, SUBSCRIPT