explode和explode_outer之间的区别

本文介绍了explode和explode_outer之间的区别的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

爆炸和 explode_outer ?这两个函数的文档是相同的，并且两个函数的示例是相同的:

What is the difference between explode and explode_outer? The documentation for both functions is the same and also the examples for both functions are identical:

SELECT explode(array(10, 20));
 10
 20

和

SELECT explode_outer(array(10, 20));
 10
 20

火花源表明这两个功能之间存在差异

The Spark source suggests that there is a difference between the two functions

expression[Explode]("explode"),
expressionGeneratorOuter[Explode]("explode_outer")

但是 expressionGeneratorOuter 与表达式?

推荐答案

爆炸通过忽略数组中的空值或空值为数组或映射列中的每个元素创建一行，而 explode_outer返回数组或映射中的所有值，包括null或空.

explode creates a row for each element in the array or map column by ignoring null or empty values in array whereas explode_outer returns all values in array or map including null or empty.

例如，对于以下数据框-

For example, for the following dataframe-

id | name | likes
_______________________________
1  | Luke | [baseball, soccer]
2  | Lucy | null

爆炸提供以下输出-

id | name | likes
_______________________________
1  | Luke | baseball
1  | Luke | soccer

explode_outer 提供以下输出-

id | name | likes
_______________________________
1  | Luke | baseball
1  | Luke | soccer
2  | Lucy | null

SELECT explode(col1) from values (array(10,20)), (null)

+---+
|col|
+---+
| 10|
| 20|
+---+

同时

SELECT explode_outer(col1) from values (array(10,20)), (null)

+----+
| col|
+----+
|  10|
|  20|
|null|
+----+

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