element_at

SinceVersion 1.2.0

element_at

description

Syntax

  1. T element_at(ARRAY<T> arr, BIGINT position)
  2. 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 negative number.

notice

Only supported in vectorized engine

example

positive position example:

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

negative position example:

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

keywords

ELEMENT_AT, SUBSCRIPT