outer组合器
description
在table function的函数名后面添加_outer后缀使得函数行为从non-outer变为outer,在表函数生成0行数据时添加一行Null数据。
example
mysql> select e1 from (select 1 k1) as t lateral view explode_numbers(0) tmp1 as e1;
Empty set
mysql> select e1 from (select 1 k1) as t lateral view explode_numbers_outer(0) tmp1 as e1;
+------+
| e1 |
+------+
| NULL |
+------+keywords
outer