array_except
description
Syntax
ARRAY<T> array_except(ARRAY<T> array1, ARRAY<T> array2)返回一个数组，包含所有在array1内但不在array2内的元素，不包含重复项，如果输入参数为NULL，则返回NULL
notice
仅支持向量化引擎中使用
example
mysql> set enable_vectorized_engine=true;
mysql> select k1,k2,k3,array_except(k2,k3) from array_type_table;
+------+-----------------+--------------+--------------------------+
| k1 | k2 | k3 | array_except(`k2`, `k3`) |
+------+-----------------+--------------+--------------------------+
| 1 | [1, 2, 3] | [2, 4, 5] | [1, 3] |
| 2 | [2, 3] | [1, 5] | [2, 3] |
| 3 | [1, 1, 1] | [2, 2, 2] | [1] |
+------+-----------------+--------------+--------------------------+
mysql> select k1,k2,k3,array_except(k2,k3) from array_type_table_nullable;
+------+-----------------+--------------+--------------------------+
| k1 | k2 | k3 | array_except(`k2`, `k3`) |
+------+-----------------+--------------+--------------------------+
| 1 | [1, NULL, 3] | [1, 3, 5] | [NULL] |
| 2 | [NULL, NULL, 2] | [2, NULL, 4] | [] |
| 3 | NULL | [1, 2, 3] | NULL |
+------+-----------------+--------------+--------------------------+
mysql> select k1,k2,k3,array_except(k2,k3) from array_type_table_varchar;
+------+----------------------------+----------------------------------+--------------------------+
| k1 | k2 | k3 | array_except(`k2`, `k3`) |
+------+----------------------------+----------------------------------+--------------------------+
| 1 | ['hello', 'world', 'c++'] | ['I', 'am', 'c++'] | ['hello', 'world'] |
| 2 | ['a1', 'equals', 'b1'] | ['a2', 'equals', 'b2'] | ['a1', 'b1'] |
| 3 | ['hasnull', NULL, 'value'] | ['nohasnull', 'nonull', 'value'] | ['hasnull', NULL] |
| 3 | ['hasnull', NULL, 'value'] | ['hasnull', NULL, 'value'] | [] |
+------+----------------------------+----------------------------------+--------------------------+
mysql> select k1,k2,k3,array_except(k2,k3) from array_type_table_decimal;
+------+------------------+-------------------+--------------------------+
| k1 | k2 | k3 | array_except(`k2`, `k3`) |
+------+------------------+-------------------+--------------------------+
| 1 | [1.1, 2.1, 3.44] | [2.1, 3.4, 5.4] | [1.1, 3.44] |
| 2 | [NULL, 2, 5] | [NULL, NULL, 5.4] | [2, 5] |
| 1 | [1, NULL, 2, 5] | [1, 3.1, 5.4] | [NULL, 2, 5] |
+------+------------------+-------------------+--------------------------+
keywords
ARRAY,EXCEPT,ARRAY_EXCEPT