array_difference
Description
Syntax:
ARRAY<T> array_difference(ARRAY<T> arr)This function calculates the difference between adjacent array elements. It returns an array where the first element is 0 and the second is the difference between a[1] - a[0]. If NULL exists, it will return NULL
Note:
It is only supported in vectorized engine.
Example
mysql> set enable_vectorized_engine=true;
mysql> select *,array_difference(k2) from array_type_table;
+------+-----------------------------+---------------------------------+
| k1 | k2 | array_difference(`k2`) |
+------+-----------------------------+---------------------------------+
| 0 | [] | [] |
| 1 | [NULL] | [NULL] |
| 2 | [1, 2, 3] | [0, 1, 1] |
| 3 | [1, NULL, 3] | [0, NULL, NULL] |
| 4 | [0, 1, 2, 3, NULL, 4, 6] | [0, 1, 1, 1, NULL, NULL, 2] |
| 5 | [1, 2, 3, 4, 5, 4, 3, 2, 1] | [0, 1, 1, 1, 1, -1, -1, -1, -1] |
| 6 | [6, 7, 8] | [0, 1, 1] |
+------+-----------------------------+---------------------------------+Keywords
ARRAY, DIFFERENCE, ARRAY_DIFFERENCE