array_union
array_union
array_union
description
Syntax
ARRAY<T> array_union(ARRAY<T> array1, ARRAY<T> array2)
返回一个数组，包含array1和array2的并集中的所有元素，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_union(k2,k3) from array_type_table;
+------+-----------------+--------------+-------------------------+
| k1 | k2 | k3 | array_union(`k2`, `k3`) |
+------+-----------------+--------------+-------------------------+
| 1 | [1, 2, 3] | [2, 4, 5] | [1, 2, 3, 4, 5] |
| 2 | [2, 3] | [1, 5] | [2, 3, 1, 5] |
| 3 | [1, 1, 1] | [2, 2, 2] | [1, 2] |
+------+-----------------+--------------+-------------------------+
mysql> select k1,k2,k3,array_union(k2,k3) from array_type_table_nullable;
+------+-----------------+--------------+-------------------------+
| k1 | k2 | k3 | array_union(`k2`, `k3`) |
+------+-----------------+--------------+-------------------------+
| 1 | [1, NULL, 3] | [1, 3, 5] | [1, NULL, 3, 5] |
| 2 | [NULL, NULL, 2] | [2, NULL, 4] | [NULL, 2, 4] |
| 3 | NULL | [1, 2, 3] | NULL |
+------+-----------------+--------------+-------------------------+
mysql> select k1,k2,k3,array_union(k2,k3) from array_type_table_varchar;
+------+----------------------------+----------------------------------+---------------------------------------------------+
| k1 | k2 | k3 | array_union(`k2`, `k3`) |
+------+----------------------------+----------------------------------+---------------------------------------------------+
| 1 | ['hello', 'world', 'c++'] | ['I', 'am', 'c++'] | ['hello', 'world', 'c++', 'I', 'am'] |
| 2 | ['a1', 'equals', 'b1'] | ['a2', 'equals', 'b2'] | ['a1', 'equals', 'b1', 'a2', 'b2'] |
| 3 | ['hasnull', NULL, 'value'] | ['nohasnull', 'nonull', 'value'] | ['hasnull', NULL, 'value', 'nohasnull', 'nonull'] |
| 4 | ['hasnull', NULL, 'value'] | ['hasnull', NULL, 'value'] | ['hasnull', NULL, 'value'] |
+------+----------------------------+----------------------------------+---------------------------------------------------+
mysql> select k1,k2,k3,array_union(k2,k3) from array_type_table_decimal;
+------+------------------+-------------------+----------------------------+
| k1 | k2 | k3 | array_union(`k2`, `k3`) |
+------+------------------+-------------------+----------------------------+
| 1 | [1.1, 2.1, 3.44] | [2.1, 3.4, 5.4] | [1.1, 2.1, 3.44, 3.4, 5.4] |
| 2 | [NULL, 2, 5] | [NULL, NULL, 5.4] | [NULL, 2, 5, 5.4] |
| 4 | [1, NULL, 2, 5] | [1, 3.1, 5.4] | [1, NULL, 2, 5, 3.1, 5.4] |
+------+------------------+-------------------+----------------------------+
keywords
ARRAY,UNION,ARRAY_UNION
