COLLECT_LIST

description

Syntax

ARRAY<T> collect_list(expr)

返回一个包含 expr 中所有元素(不包括NULL)的数组，数组中元素顺序是不确定的。

notice

仅支持向量化引擎中使用

example

mysql> set enable_vectorized_engine=true;
mysql> select k1,k2,k3 from collect_test order by k1;
+------+------------+-------+
| k1   | k2         | k3    |
+------+------------+-------+
|    1 | 2022-07-05 | hello |
|    2 | 2022-07-04 | NULL  |
|    2 | 2022-07-04 | hello |
|    3 | NULL       | world |
|    3 | NULL       | world |
+------+------------+-------+
mysql> select k1,collect_list(k2),collect_list(k3) from collect_test group by k1 order by k1;
+------+--------------------------+--------------------+
| k1   | collect_list(`k2`)       | collect_list(`k3`) |
+------+--------------------------+--------------------+
|    1 | [2022-07-05]             | [hello]            |
|    2 | [2022-07-04, 2022-07-04] | [hello]            |
|    3 | NULL                     | [world, world]     |
+------+--------------------------+--------------------+

keywords

COLLECT_LIST,COLLECT_SET,ARRAY